"You're taking me to the same planets you took her to? ever heard of the word rebound?"

I wasn't really looking forward to "Gridlock" all that much. Don't get me wrong, like every other Doctor Who fan out there I was on the edge of my seat praying that Man Utd vs Watford didn't go into extra time, but even so I wasn't looking forward to "Gridlock" with the same sort of bated breath that I am, for example, the "Human Nature" two-parter, or even next week's Dalek story.

I think that this is largely down to "New Earth". David Tennant's first regular outing as the Doctor was a bit too light for my liking; it was fast and it was fun, but it didn't possess the same sort of weight that a lot of my favourite new series episodes do. However, whilst "Gridlock" may be set on New Earth, this time around the tone is much darker.

Russell T. Davies' script is a rare example of a Doctor Who story that is about the Doctor. In this episode we tend to see things from his point of view, as opposed to his companion's. At the start of the episode when Martha incessantly interrogates him about his homeworld, the whole audience is cringing because we know she's opening up a can of worms. She sends the Doctor off into his own little world, talking about Gallifrey as if it still exists, vividly describing the magnificent Citadel and the "burnt orange sky".

However, as much as the emphasis of "Gridlock" is on the Doctor, the episode certainly does not neglect his newest friend. This episode sees Martha have an "End of the World"-style epiphany. When she is kidnapped by Milo and Cheen, much like Rose on her first trip into the far future she realises that she could die and that her parents would never know her fate. She realises that she doesn't even know the Doctor at all.

"I didn't really think? I just followed the Doctor? There's so much he never says?"

Yet she trusts him. Implicitly.

The plot itself is intriguing in concept and audacious in scale. "New Earth" saw Russell T. Davies get on his soapbox about 'animal' experimentation, but here he chooses a topic that far more people can relate to; one that affects almost everybody's daily life - traffic! On the motorways of New Earth it takes on average ten years to travel six miles. The pollution is so dense that if you breathe it for any length of time it is rumoured to make your head explode. Untold numbers of cars are packed into the undercity, not only in horizontal queues but also in vertical ones. It is the ultimate Gridlock. A prison. A nightmare.

"You think you know us so well, Doctor. We are not abandoned. Not while we have each other."

Somehow though there is charming and uplifting sense of unity amongst this mass of imprisoned 'humanity'. Their singing of "The Old Rugged Cross" and "Abide By Me" in unison is a moving and a powerful moment, and their 'Friends Lists' are a wonderful reflection on modern society and people's inexplicable obsession with things like My Space and Facebook. Says I, www.myspace.com/historyofthedoctor. Here once again, Davies manages to unify the profound and the (seemingly) trivial into one whole that manages not only to entertain, but also make a strange sort of sense.

And then living amidst the gas in the depths of the Fast Lane lurks an old foe of the Doctor's. In all the pre-season hype many speculated about which 'old enemy' would be returning. Zygons? Ice Warriors? I would never in a million years have guessed the Macra would be making a comeback! It was the biggest shocker since the Nimon showed up in "Seasons of Fear"! And what's more, they're awesome. The C.G.I. Macra look phenomenal. Okay, they could have been substituted for any ravenous monster - new or old ? but their inclusion is a lovely nod to the series' long history; it certainly can't hurt. In "Smith and Jones", the Doctor appeared to know all about the Judoon, yet they never showed up in the classic series. His knowledge of the Macra (and his lovely pr?cis of "The Macra Terror") is no more conspicuous than his familiarity with the Judoon. Newbies won't even have blinked.

"Gridlock" is also populated with a trademark collection of Davies' weird and wonderful aliens. Red people. White people. Hippies. Nudists. Even a Mr. Benn look-alike! And of course we have the return of the Cat-People, albeit in a much more benevolent guise. Brannigan is a wonderfully endearing character; Ardal O'Hanlon imbues the cat with his innate amiability so that even the Doctor can't help but get over his recent bad experiences with his kind. Until "Fear Her", the Doctor had always been a cat-lover, and he should be again in my opinion! I wanted him to keep one of the kittens! Maybe he'll get a cat in "Human Nature"?

In it's darkest moments, "Gridlock" is also an allegory about the dangers of drugs. Those cars may all be trapped on the motorways, but that is a much better fate than the armageddon that 'Bliss' wrought upon the cities on New Earth. Literally everyone above ground is dead and were it not for the Face of Boe, those in the undercity would have perished alongside them.

Now the return of Boe is something that I was very excited about. I'm not ashamed to admit that I had goosebumps as his theme tune played (you know the show is a hit when a character who has been in just three or four episodes has his own theme) and I heard his telepathic voice. His entirely expected demise was also an incredibly touching moment, but even that was overshadowed by his final revelation:

"Know this, Time Lord. You are not alone."

And with that he dies, leaving the Doctor to puzzle out the conundrum. The Doctor knows that his world is gone and that he is last of his people. He is also sure that Boe wasn't referring to Martha ? in fact, that possibility was dismissed far too quickly for Martha's liking. So what could it mean? I think we all know really, the only question is how? Personally I'm hoping for a characteristically blas? explanation: "Ah, so you escaped from?"

The final scenes of "Gridlock" are a thing of beauty, both literally and figuratively. The mass exodus from the undercity is a stunning image; the splendour of New, New York looks like a stunning hybrid of contemporary New York and Coruscant from the Star Wars prequels. The 'folding chair' scene is an equally beautiful character moment; it marks a key stage in the relationship between the Doctor and Martha, and it also sets up next week's Dalek adventure very nicely. Under the burnt orange sky of New Earth, the Doctor sits Martha down and tells her of the Time War.

"I lied to you 'cos I liked it. I could pretend. Just for a bit I could imagine they were still alive underneath the orange sky. I'm not just a Time Lord. I'm the last of the Time Lords. The Face of Boe was wrong; there's no-one else. They've all gone now. My family. My friends. Even that sky."

The only negative comments I would have about "Gridlock" are that a couple things didn't make all that much sense to me. If it takes ten years to drive six miles, why not walk? And what happens to the Macra? Do they live happily ever after in the gaseous Fast Lane?

Those two points aside, "Gridlock" came as a wonderful and welcome surprise to me. The quality of this third series continues to astound me. Doctor Who now has more episodes in the canon than in the entire Star Trek franchise and, to end on a clich?, year after year it just keeps getting better. It's three hits out of three for Series Three.

In the days when I used to partake of an ale or 12 of an evening and come home with the munchies, I would scour the kitchen and deposit various (vaguely edible) objet da in a frying pan, apply severe heat, and see what the results tasted like. It was a bit hit and miss. Sometimes, it found the spot, and I prepared my application form for Ready Steady Cook. On other occasions, it set me en route to frequent conversations with the big white telephone in the bathroom. I'm getting to the point . . .

Gridlock was a bit like one of those death-or-glory fry ups - writer Russell T Davies chucked a lot of ingredients in there. But you know what? The results were mighty tasty.

I was rather ambivalent about this one pre-transmission - neither The End Of The World nor New Earth are anywhere the top of my favourite New Who episodes, so the prospect of a third trip to Year Five Billion (ish) didn't greatly enthuse me. However, as part of RTD's attempts to build a new mythology for the series, the logic of The Doctor taking new companion Martha to New Earth for her first trip into the future was sound.

It was a very bleak future, though - the TARDIS landing in a distinctly lo-tech slum, where chemically-enhanced patches were sold to the desperate few who lived there. Before The Doctor could investigate further, he faced a more-pressing matter - rescuing Martha, who was kidnapped by a young couple, to provide them the numerical requisite to speed their passage on the severely-congested motorway. To Martha's horror, she then finds out this is the traffic jam from Hell, taking years to travel a short distance in flying cars which double as tiny mobile homes. And not only that, something terrifying is lurking in the depths below the gridlock.

Meanwhile, The Doctor has also joined the traffic jam in pursuit of his young charge, hitching a lift with Brannigan, a cat person, and his human wife. Realising that there's a probability the jam never ends when he hears Brannigan has been flying this road for 12 years, The Doctor sets hopping from car to car when he encounters an old acquaintance, the giant crab creatures, the Macra, which are the monsters from the depths, devouring those in cars who venture too low. Then, The Doctor meets another familiar face, Novice Hame, the cat nurse from New Earth. Hame has been tending the mysterious Face Of Boe, and teleports herself and The Doctor to the dying Boe's side.

The Doctor learns that the inhabitants of New New York (so good they named it 15 times) had been all but wiped out by a virus, and the sole survivors were trapped below ground for their own safety. Boe and The Doctor combine to bring the motorists back into the now-disease-free city and saves Martha from the claws of the Macra.

Sadly, the effort expanded by Boe leads to his death, but not before he imparted his great secret to The Doctor - "You are not alone" . . . does that mean The Doctor isn't the last of the Time Lords?

I really enjoyed this episode, maintaining the consistently-high standard at which this Series 3 has started, and this was my favourite of the "New Earth trilogy". Of course, it was far too short to be developed properly at 45 minutes, but that's the nature of these single episodes. The pace is absolutely unrelenting, but the highlight of the episode for me was when it did slacken at the end to allow some lovely interaction between the show's stars.

In the opening scenes in the TARDIS, The Doctor is extremely cagey about revealing details of who he is and where he's from. In fact, he even goes as far as to lie when he gives the impression Gallifrey still exists. But by the close of this adventure, he has realised Martha is someone in whom he can confide, and gently explains about the Time War, how he is the last of his race (despite what Boe says) and mention of the Daleks sets up next week's episode nicely. A touching closing scene, totally in contrast to the high-octane action beforehand and beautifully played by David Tennant and Freema Agyeman. Three episodes in, and Freema has barely put a foot wrong. She's been such an impressive addition to the show that the loss of the excellent Billie Piper hasn't been felt at all.

The death of Boe was also quite moving - wouldn't go as far as to say I shed a tear for old giant rubber chops, but what a great piece of work from the prosthetics team he was. Sad to see him go. Of course, his dying message has to be significant in the context of the series - and the wordage was one of the worst-kept secrets in Doctor Who history.

Guest star Ardal O'Hanlon put in a pleasing performance as a cat person, and it was a decent supporting cast. Director Richard Clark did a fine job of delivering the claustrophobic feel required inside the cars, and there was hints of Blade Runner in there, plus numerous other sci-fi genres, RTD never having made any secret of the fact he's quite happy to borrow - to be generous - ideas from elsewhere, and sourcing Judge Dredd as his inspiration for the bowler-hatted businessman encountered by The Doctor in one of the cars. Also loved the scenes of The Doctor dropping from car to car - gave a real idea of scale.

The Macra are borrowed from Doctor Who history - 1967, to be precise, and it was a nice touch to revive a little-known historical monster. The Patrick Troughton story, The Macra Terror, in which they featured, is visually familiar to few. However, a nice little nod to fans. I didn't think the Macra were quite as well realised from a CGI point of view as the flying cars, but another impressive effort from The Mill, as the bar continues to be inched up episode to episode.

Eight out of 10. Slightly the pick of the three episodes so far. Great stuff - but looking forward to getting a two-part story now, to allow the story a bit more time. And can't wait to have the pepperpots back, of course . . .

The short summary: I liked this one a LOT more than I expected I would, given the setup. Davies shows no signs of giving up his excessive indulgences, but his gifts -- the characterisation of the Doctor, the dialogue, the lovely amounts of real emotion he works into those scripts -- all win out.

That said, that doesn't mean I don't half have some nits to pick. Martha isn't the only one who groaned when she found out she's retreading planets Rose visited, I was right there with her. There was absolutely ZERO need to revisit New Earth to make this story work (particularly as the Face of Boe was seen LEAVING the planet at the end of "New Earth"), other than getting to hear David spit out "Newnewnewnewnewnewnewnew York" again (and it's fun, but that's still no good reason!).

There were some logic problems as well. As the story really begins, we found our heroes have landed in NNY's undercity. It's revealed later that this area is completely sealed off, but when we first see it, it's raining (how does that work in a sealed off area, we wonder?). That whole sequence paid a nice homage to both Blade Runner (the rain, the drugs) and Brazil (kidnapping Martha because you need a third adult to get into the Fast Lane?!), and was the first of many surprises in this story that gave it a more original feeling than we'd reckoned.

Much of the rest of the episode takes place on one set, the (continually re-dressed) car that people live in. One wonders why they can't just walk to where they're going (easily explained a half- dozen ways, but not made clear in the story), or why they want to get away since the non-Motorway part of the undercity doesn't seem THAT bad, but put those things aside and enjoy the campy, overplayed stereotypes of drivers the Doctor cleverly comes across (a very Sixth Doctor idea of getting from A to B, I felt).

My other major issue with Gridlock is down entirely to the writer, Davies. As with the Daleks, I do think RTD is overamping the necessity for a "gay statement" in nearly every episode he writes. I love gay people but this nearly-constant reference to them (particularly when the story has to take a significant detour to get there) is wearing. Note to RTD: No Daleks AT ALL next season, and you can only put gay characters in if they're significant to the plot (like Capt. Jack).

Lastly, I'm afraid I didn't care much for Brannigan. Unlike most people in similar roles/disguises, Brannigan came over painfully as a guy with lots of makeup on his face rather than selling the character. I felt much the same way about the Absorbaloff (Peter Kay), but I recognise that sometimes the public love of a personality (like Ken Dodd) overcomes the lack of sincerity in their performance. I don't think Brannigan (Ardal O'Hanlon) has that kind of admiration. I also think I may be getting old, since I was a bit bothered by the idea of a human female giving birth to kittens. Probably just me though.

So a few things not to like. There were, as balance, plenty of things to like. I was surprised, and deeply moved, by the inclusion of the "Old Rugged Cross" scene in the show. This is precisely what I love about Doctor Who: no other show throws me these curveballs so delightfully well. It was a really touching moment beautifully handled, and again at the end when they sang "Abide in Me."

The revelation of the "devolved" Macra was a nice touch, but if they wanted a true homage to the original story they could have at least put together ONE scene where the Macra weren't CGI (specifically, I wanted one giant half-offscreen cardboard claw to grab someone!).

Martha continues to find her feet, but the qualities that make her a companion are starting to come to the fore. Whatever worries I have about this "crush" business are starting to fade. She can even say things Rose would have said and it doesn't bother me a bit.

At last we come to Novice Hame and the Face of Boe. I'll admit it for the record -- I got a tear in my eye when Boe passed on. This is the only show in the entire world that can make me cry for a prop head. Damn that's good television. Anna Hope (as Hame) really got to show all sides of her character, and I was greatly amused when the Doctor recognises her and moves to embrace her -- before remembering that she was attacking him last time they met.

I was annoyed that Boe's "last great secret" as prophecied in "New Earth" was merely to let the Doctor know that he is both the last of his kind (Time Lord) *and* not alone. I think I've got that meaning worked out, but of course we'll see. Martha finally puts her foot down and demands to be brought up to speed, and the Doctor reluctantly agrees -- a nice scene nicely realised.

Overall, "Gridlock" was better than "Smith & Jones," and probably on par with "The Shakespeare Code." It's a tribute to the production team that they can go from richly historical location shooting at the Globe Theatre to a small prop car set on a greenscreen stage in Wales and still make everyone buy into it. Season Three might not yet have really taken off, but while we wait for the "Fast Lane" of Important Stories with Major Plot Revelations, the entertainment factor we've seen so far is pleasingly high.

Faith, hope and charity are now major themes in the new series and Russell T. Davies puts further emphasis on them in his latest, and for the moment, best script for the series. Has Russell suddenly got that old time religion? 'The Old Rugged Cross' and 'Abide With Me' heard in the same episode! No, he's not changed his mind but is merely showing how faith works as a concept without recourse to singling out any particular deity or belief system in which to place your trust. The only trust and faith you need is the one Martha clearly shows us, the faith in the Doctor, and a notion that even under the greatest pressures all creeds and colours can have trust and faith in each other as thinking, breathing beings. Davies' use of hymns is not just a symbolic representation of this but it's also a clever critique of how organised religion often provides an opiate for the masses, a pacifying salve for an unquestioning society.

'Gridlock' comes over as 'The Pilgrim's Progress' gene-spliced with the venerable '2000AD' comic. It's a giddy vortex of comic strip images, very cinematic in their scope, and a claustrophobic dystopian tone poem with nods to 'The Fifth Element' and 'Blade Runner' as well as the classic series 'The Macra Terror'. It also reinforces Davies' obsession with vertical narrative. We travel from the Macra (devils in Hell?) infested depths, through layers of trapped cars (souls) and ultimately into 'heaven' when the sky splits open. The episode is very Dante-esque in approach, with everyone trapped in a bizarre, smog filled Purgatory and requiring either the Doctor or the Face Of Boe to lead them through the various circles of Hell, including the Over City, into a climactic light-filled redemption. How 'religious' is this episode!? I don't think it's making any comments about any particular religion as such, just using archetypes and imagery to illustrate various points about the redeeming power of trust and faith. In fact, the book-ending of the story with those quiet moments about Gallifrey are perhaps indicative of Davies' attempt to say that even though the old time religion of the Time Lords, once itself a choked gridlock of elitist attitudes, has gone it's the Doctor's clear love for his home world that ensures that something remains of the balancing force of that supposedly dead race.

It may be full of bonkers ideas, but Doctor Who has never been about getting the science and the realism 'right'. World building in the series should never be to the detriment of the drama and it would be churlish to criticise the vagaries of the concepts here. It is simply the idea of different kinds of beings living in this way that we need to refer to rather than the exact domestic arrangements or the technobabble that allows them to fly their cars. It's all part and parcel of the visual metaphors that the story uses. I loved the way the story switched from one couple to another, giving us different views into each of their private little worlds. Certainly seeing the naturists, the bizarre black cat and its accompanying virgin brides, the city gent et al are both hilarious and surreal moments in a dark, sinister story where drugs wipe out an entire city population and the survivors have to run the gauntlet of giant crabs. The inclusion of the Macra was a lovely nod to the past and they were simply there as another flavour to the story and to have expected the story to focus on them would have been na?ve. This is a Russell T script, after all.

The death of Boe, like the death of King Arthur, is a significant step towards a greater narrative we have yet to see play out. The literal death of the 'god-head' here does signify that Davies is more interested in the collective power of people rather than their subservience to a God. The flip side of that is that of course without Boe none of those trapped in the circles of Hell would have survived. Another instance of self-sacrifice for the greater good in the series that seems to follow in the wake of God-like figures and I'm sure we'll see more of this as the series plays out this year.

Beyond the deeper questions that the script throws at us is the outstanding performance from David Tennant. He lies to Martha about Gallifrey and by the episode's conclusion understands that he can't get away with it and must be open to her about his status as the last of his race. He and Boe are both ancient, lonely creatures and both realise that they must be true to their nature without jeopardising the lives of others. Tennant's final scene with Martha in the alleyway should be seen as the single example of why this actor is right for the role. It brims with sadness, lost hope and is played as a confessional between them both. And he finally lets Martha in.

Agyeman continues to excel, with Martha's exuberant obstinacy, honesty, and no nonsense intelligence shining through here and allowing her to put a singular stamp on the role. Ardal O'Hanlon as Brannigan and Anna Hope as Novice Hame were great supporting characters and praise should go to the stunning make ups by Neill Gorton.

Finally, The Mill should also be congratulated for their work on the episode, turning the gridlock, the city and the Macra into spectacular images that continue to make this series such a thrilling experience. You really did get a sense that all departments were pushing to make this an episode to remember.

Overall, it's a fitting conclusion to the New Earth trilogy started in 'End Of The World' containing some very interesting views about organised religion, the class system and population control. A bold script from Davies for a third series that doesn't even want to rest a little on its laurels.

Well, that was? odd. 'Gridlock' manages to be entertaining whilst deeply flawed, succeeding against the odds, but only just. I enjoyed it more than it deserved really, which is especially unexpected as I have several major criticisms of it.

The basic premise of 'Gridlock' manages to be simultaneously ludicrous and amusingly bizarre, with a world in which everyone is perpetually trapped in a traffic jam on an endless motorway to nowhere having merit as a novel modern urban nightmare. It doesn't stand up to any real scrutiny in terms of logic, and the total lack of explanation for why huge numbers of couples haven't gone mad from cabin fever and slaughtered each other seems less like an oversight and more like something that Davies has ignored purely because he hasn't got a good explanation for it. Still, it makes for an interesting if unlikely set-up.

Then there are the Macra. For anyone unfamiliar with 'The Macra Terror' or indeed the classic series as a whole, the inclusion of the Macra here as big scary monsters probably works quite well, but for two small points. Firstly, unfamiliar with the creatures or not, the line about them once being "the scourge of this galaxy" is yet another example of Davies' style of "tell not show" writing, upping the ante by using throwaway dialogue to make his villains/monsters seem like a more formidable threat than they otherwise might, and it's terribly, terribly lazy (and if you are familiar with the creatures, it's about as convincing as being told that the Krotons once ruled the entire universe). Secondly, they vanish from the plot, their function fulfilled, as soon the Doctor opens the roof of the motorway, and they aren't mentioned again. It would have been nice, and not I feel too much to ask, to find out what happens to them. Do they all die when the fresh air is let in? Do the inhabitants of New New York plan on clearing them out at a later date? Or are they just left to lurk in the under city like unusually big rats?

On the other hand, viewers familiar with 'The Macra Terror' get the cheap fannish thrill of a largely unexpected old monster making a comeback, but I ended up wondering why Davies bothered. Given their modus operandi in 'The Macra Terror', I was briefly expecting that the Macra were responsible for the traffic jam and were using it as a sort of battery farm/flying larder, so the revelation that they have devolved into mere beasts and have simply mindlessly taken advantage of an ecological niche felt like a wasted opportunity. Although it wasn't as disappointing as realising that Davies' obsession with Joss Whedon has now led him to rip-off bits of the plot of Serenity. And whilst the Macra aren't exactly revered as the best designed monsters in Doctor Who, their claws here are so disproportionately big that instead of wondering if the car carrying Martha would escape, I found myself wondering why the Macra don't keep toppling onto their fronts.

Speaking of Martha, she gets rather a good outing here, and Agyeman continues to impress. Despite the teeth-grindingly annoying "rebound" conversation, and Martha speculating on whether the Doctor really likes her or just enjoys company (which, incidentally, briefly makes her sound like a prostitute, which is amusing but presumably unintentional), she gets to show her intelligence again when she realises that the Macra won't be able to find the car if they power down its systems. Her brief anger at Cheen taking drugs whilst pregnant is a nice moment, since it is a perfectly believable reaction for a medical student, but her best scene comes at the end, when she forces the Doctor to tell her what happened to his people in a way that Rose would never have got away with. Given the direction that this series is rumoured to be going in, and with the Daleks returning in the next episode, this not only works as a good character moment, but provides a timely catch-up for casual viewers into the bargain.

It's also a good scene for the Doctor, with Tennant, continuing to show restraint, emoting convincingly as he talks about Gallifrey and the Time War. He generally gets a good episode too, especially when he's dropping from car to car, and he again gets to save an entire world. Some reviewers have already complained that throwing a big lever constitutes another Davis ex machina ending, but to be fair it feels more logical than some such finales, as repairing the city's systems seems like a sensible approach to the problem in hand. My main problem with the Doctor concerns Davies' typically unsubtle anti-drugs message, as the Doctor waltzes into a street of small businesses that he has no reason to believe are anything other than perfectly legitimate and high-handedly and pompously threatens to close them down. So presumably Russell, he'll be taking the same stance with off-licenses and pubs the next time he's in present day England, or don't you have a self-righteous axe to grind with that particular drug?

As for the supporting characters, only Ardal O'Hanlon's Brannigan stands out, and only because he's quite likeable, but at the same time all of the others work perfectly well here and the old ladies are nicely handled, with one of them cheerfully drawing on a passion for car-spotting to trace Martha for the Doctor. The actors playing the two people who die in terror in the pre-credits sequence also deserve a mention, for conveying fear very convincingly. Although the self-conscious eccentricity of the man in the bowler hat is irritating, and the idea of a woman giving birth to cats falls firmly into the bizarre category. In terms of production, Richard Clarke's direction is adequate: there's nothing especially outstanding, but I've seen worse and it gets the job done. And anyone reading this can take it as read that the music of Murray Gold, the twenty-first century equivalent of Keff McCulloch, detracts from my enjoyment of any episode in which it appears.

And then we have the Face of Boe. The third and final meeting between the Doctor and him promised back in 'New Earth' takes place and we learn his last great secret, which is that the Doctor is not alone. Which might have been a great dramatic moment were it not for the fact that the tabloids have already blown the big surprise in store later in the series, and had Davies not already revealed the Face of Boe's secret in the tie-in book Monsters and Villains some two years ago and decided that he wanted to use it in the series. Normally, I'd accept that as a fan I'm more likely to have picked up spoilers than the casual viewer, but lots of people (unfortunately) read the tabloids, and I'm assuming that many of the younger new viewers have read Monsters and Villains, so it does rather seem like an anticlimax rather than an exciting surprise revelation. Nevertheless, if the series is going in the direction that many of us have led us to believe, it does work in that context as part of the build-up. I just hope Davies doesn't do anything as witlessly stupid as the Bad Wolf revelation come the series finale?

Just superb, I'm not sure what has given the production team behind Doctor Who a kick up the rear end but they have certainly opened series three with some of the most ambitious and spectacular episodes of the series yet. Gridlock features some imaginative concepts, some decent world building (in 45 minutes!), great characterisation and a few excellent shocks. As a overall package, script, FX, music, acting and direction it is easily my favourite of the year so far, although there really hasn't been any losers.

Has something depressing happened to Russel T Davies between series two and three? Smith and Jones and Gridlock both feel much more dark and gritty than his work on previous series and it is totally to the advantage of his latest scripts. Whilst I do enjoy the giddy thrill of stories such as World War Three, it is episodes like Gridlock, that play it straight and go for the chills, that I love the most. I love this vision of the future, as Russel says in the Confidential this week it is ripped totally out of 2000AD but where is the harm in that when it is pulled off this well? A world of smoke and exhaust fumes, of back alley drug dealing and gunplay. It is like re-visiting the Eric Saward era but it feels special because we do not inhabit this universe every week.

Add to the world building some marvellous concepts, which give this episode a unique feel. I love the idea of selling moods, simply because it is pretty damn obvious that if this was the case in our world it catch like the latest mobile phone. It reminds me slightly of Gareth Roberts' programmable emotions from Only Human. Also the thought of the Gridlock, the ultimate in traffic jams where you could going around and around in circles on the motorway is too frightening for words. What I especially liked about these two ideas is that they are not gratuitous, they have a purpose in the story, the entire plot is built around them and both lead to intriguing twists, one horrific and one which turns your entire perception of the episode on its head. It strikes me that Russel T Davies' has suddenly figured out how to plot a perfect Doctor Who episode, with no flabby bits and lots of payoff. I cannot imagine us getting another The Long Game this year.

So what of the Doctor and Martha and their burgeoning relationship? Who would have ever thought that switching from one companion to the next would have such emotion mileage? In the past the Doctor has just swapped one companion for another. Even companions such as Jo Grant, who the Doctor clearly has a hard time saying goodbye to; he soon forgets she ever existed when Sarah Jane comes along in the next story. I'm not sure if I buy that his relationship with Rose would mean so much to him that he would be quite so rude as he has been to Martha but it does keep the dynamics of their relationship interesting. The trouble with the Doctor and Rose last year was that after School Reunion their relationship became a little predictable, they loved each other and that was fine but for week after week there was nothing new to spice things up. It looks as though the production team have decided they don't want things to get too easy for the TARDIS crew this year and I can still forsee some bumpy times ahead.

Martha is such a terrific character played by such an enthusiastic performer it is impossible not to like her. Freema Agyeman has terrific chemistry with David Tennant already and her solo exploits in this episode leave us with no illusion that she can hold her own. What is interesting is how this episode plays with her feelings for the Doctor. Initially everything is the same as last week, she is enraptured in the giddy thrill of flinging open the TARDIS doors and seeing what is outside. But it is not until she is trapped on the motorway with an unseen menace that she realises that she is on her own, on another planet and her only hope of salvation a man that she doesn't even know. It's almost as though the delirium of adventuring clears your mind of such thoughts but the fear of imminent death brings it all home. Her speech about her faith in a man that she barely knows is excellent. Even better is the last scene which highlights an important difference between her and Rose, she stubbornly refuses to enter the TARDIS until the Doctor opens out to her. This is going to be a relationship of equals.

The Doctor's plight in this story allows David Tennant to show off his acting skills even more. The series is taking the Doctor down some interesting psychological paths and watching his attempt to cover up the fact that Gallifrey is dead from novice Martha is both sweet and disturbing. He is a man of secrets but he needs to talk to somebody about them and their final scene together, where the Doctor looks on the verge of tears talking about his home is very touching. There is of course the Face of Boe's almighty secret but you will have to watch the episode to find that out. Needless to say I think the Doctor has a disquieting time ahead.

Visually this episode is amazing. Recently I have been comparing Doctor Who's production values with SF stalwarts such as Battlestar Galactica and Stargate but for sheer imagination it is topping even those. The Gridlock itself is masterfully artful but images such as the city in sunlight and the Doctor jumping between cars are worthy of a feature film. The BBC should be justifiably proud of their FX work these days and the viewers should reap some pleasure too, it is because we have been watching and buying the goods that the BBC have had such faith in the show and pumped so much budget into its blood.

There is one special effect that came as a total surprise. Do you recall when fandom jumped up in joint hurrah when the Cybermen returned in Earthshock? I had chills down my spine when this week's monster was revealed. I couldn't stop going on about it and Simon had to tell me to shut up so he could watch the rest! Needless to say this is an audacious bit of secrecy on the writers part and a collective punch in the air from fandom as an old (and pretty crappy) monster is brought back with some CGI menace. The hilarious thing is that rubbish monsters can be kept in the dark and provide more of a genuine shock but the popular monsters like the Daleks and Cybermen have to be advertised well in advance to exploit their ratings potential (see next week). Bravo.

What else is there to say about Gridlock? The last five minutes are about as uplifting as Doctor Who has been and rather than feeling twee the sentiment feels totally justifiable because we have seen the hopes and despair of these people throughout the episode. Brannigan was a great character who I hope we will see some more of in the future. And the Face of Boe's death is genuinely poignant, how on Earth can you care so much about a huge rubber head?

Other points of interest:

A woman giving birth to kittens? I couldn't get my head around that?
Ooh! Both Milo and the nudist were very, very cute.
I loved the two old dears in their chintzy spaceship. Well done, that designer!
The score from Murray Gold is again fantastic, especially when Martha's party prepare to fly through the toxic enemy.

Doctor Who goes from strength to strength and Gridlock is another example of why this is the best show on television. Sorry, what was Primeval again?