Of all the episodes in the new series, I had been looking forward to this one most of all. The idea of time being unforgiving, somehow managing to always thwart those who would interfere with it, has held much fascination for me. Importantly, the idea that the Doctor acknowledges the inflexible nature of time (despite being a Time Lord) has conveyed an overall sense of responsibility to the series.

I believe the original premise for 'Father's Day' was to have Rose confronted by an inability to change past events (her father's death), presumably becoming part of the history she was trying to avert; the story was to be devoid of special effects, instead concentrating on the attendant emotional issues and would have been a brave and unique homage to a sci-fi concept that has been much examined.

The writer, Paul Cornell, admittedly taking the story in his own direction, explored the consequences of Rose actually altering events; an opportunity was thus provided to make the point that the life of a seemingly ordinary man could possibly distort history if that man is supposed to be dead.

The duplication of the Doctor and Rose, separated by only a few minutes served to highlight the practicalities which must be observed when time travelling. Such considerations, it must be said, are not wholly original, similar ideas having been explored in other sci-fi shows and films. However, the 45 minute duration (highly criticised in relation to some previous episodes) imparts a sense of urgency and real time dilemma to the situation as these practicalities are addressed.

Although the story could have worked with the minimum of special effects, I thought the physical manifestation of Rose's actions (The Reapers) was highly effective. They retained a sense of the gothic aspects of the series, especially in the context of the church setting, and also visualised the vengeful nature of time. Almost immediately after Rose's intervention, Cornell created a sense of impending doom by initially showing our flawed universe through the eyes of the Reapers; the first handful of deaths and their ambiguous manner being in the spirit of the classic series. The mental trauma suffered by Mickey in the park was deeply disturbing, as his friends (and mother?) were removed from time; this unease was later intensified by the discarded bike and child's shoe.

The idea of an adult Rose interacting with a father she has saved while her one year old self is in close proximity was a masterstroke in terms of the wealth of possibilities which time travel can present. Rose telling her parents to stop arguing was poignantly ironic, as her desire to experience and interact with both her parents (as a family unit) resulted in her doing so in a way typical of dysfunctional families, as a mediator and referee.

In his previous contributions to Doctor Who, whether they have been books or audios, Cornell has always involved the reader/listener on an emotional level and for this rare talent, deserves kudos. I feel that, for Father's Day, the writer has again achieved this objective and there is no doubt that this is the most emotive and sympathetic episode of any series of Dr Who to be given screen time. Cornell succeeded in making the viewer care about the relationship between Rose and her father; additionally, we were shown that there are as many meaningful issues in the past of any one person as there are in the landmark events more usually visited by the Doctor and his companions.

Generally, the acting performances were polished yet natural. Eccleston portrays sympathy, empathy and admonishment in terms of the Doctor's reactions, together with a wistfulness in that, although he admires the Earth and humanity in general, he is incapable of experiencing the simplicities which he knows make humans so special. The most impressive aspect of Piper's performance was the fact that beneath the understandable exuberance at what she had achieved, there was a sense of guilt and a defensive need to justify her actions to the Doctor, whilst knowing he could not accept them.

Shaun Dingwall's portrayal of Pete Tyler's self sacrifice was beautifully balanced; rather than the tediously clichйd 'a man's gotta do...' diatribe, we were treated to the enormity of the situation being resolved in terms of a Father's responsibility for his child's actions. His awareness of his inadequacies, together with his genuine gratitude for the few hours spent with his future daughter, imbued a sense of credibility to an unlikely action on his part.

The understated direction rendered the viewing seamless in terms of fluency and characterisation. Perhaps the most impressive directorial achievement was in conveying the idea that the car was the true 'Reaper', destined to endlessly circle the church until it's hitherto thwarted purpose was fulfilled.

In terms of the causality and continuity dealt with in stories where people return to (and interact with) their own pasts, I suspect that the time paradox aspects of the episode will be criticised, yet there is no virtue in this; self righteous statements of the 'that couldn't happen because...' type have no merit because time travel is wholly theoretical and hence hypothetical. If anyone can demonstrably disprove the interpretation of the subject by people such as Wells, Heinlein, Cornell or indeed anyone who has written fiction on the subject, then please step forward: it's a non-starter.

I think, as Doctor Who fans, we have all waited and hoped for an episode that is perfect, that conforms to our own perception of what makes the show great; if adequate budgeting is discounted from the criteria, then, for many, such episodes have already happened during the classic series. The current series makes it possible to assess the show in an entirely new way; distractingly poor sets and effects are now a thing of the past and for this reason, a fresh opportunity to revisit the expectation of the perfect episode is afforded.

I have been a fan of this show for thirty years and hence I'm not fickle in the sense that, due to the big budget and higher profile, I have abandoned the old series in preference for the current one; however, I genuinely believe that, due to an understanding and incorporation of the elements of the show which have made it so thought provoking, writers such as Mark Gatiss and Rob Shearman have created near perfect episodes in the best spirit of the classic series. Cornell, however, has fashioned something which, to me, transcends the different factions of sci-fi and fantasy and is able to stand up and be counted outside of the sphere of Who fandom.

Thank you, Mr Cornell, for a perfect episode of Dr Who and a generally superb piece of television.

Brilliant. Just brilliant. Very emotional and domestic for Doctor Who, very much like 'The Butterfly Effect' but still very good.

The prelude was slightly puzzling and swift but the story was uncomplicated and it felt really realistic and genuine. A much better turn from Cornell than his previous Scream of the Shalka story which, although enjoyable, was quite generic. This was a masterpiece.

Camille Coduri was excellent and wideboy Shaun Dingwall as Rose's dad slowly and gradually found a warm place in my heart. And I have no qualms in confiding that the odd tear did drip several times during this episode.

Eccleston seemed a lot more comfortable with this material and I loved the bit when he was talking to the baby and his subsequent chat with Rose. You see the warmth between them, and Billie Piper does the out of her depth look really well.

This certainly goes as one of my favourite episodes of this series, alongside Aliens of London/World War Three (Somebody please tell me the agreed overall story title for eps 4 and 5!!!). I've been waiting since March for Steven Moffat's Blitz story as its an historical era I am interested in and the clip shown on Jonathan Ross of it seemed shit scary! Roll on, roll on!

Suddenly, unexpectedly, following on from last week's disappointment, a complete TV classic - not just for Doctor Who.

In reviewing this triumph of an episode I run out of superlatives.

Firstly, the script is as close to perfect as makes no difference. The plot is taught, both emotionally and theoretically resonant and breathes whilst maintaining a relentless pace, and still having room for some neat ironic humour which only adds to the growing drama. The direction complements this wonderfully, producing a tense, gut-wrenching spectacle, which the quality of the acting reinforces further.

Ecclestone's performance has arguably been variable during the series, and coming after his ruthlessness in "The Long Game", his compassion here might seem incompatible; but in this story we get unprecedented depths in the actor's portrayal and in the manner the character is presented. This doctor can be cold come certain situations, but his concern, affection even, for the characters in this story, is as beautiful here as in any story from the original series. He is furious with Rose for interfering with time, but this anger does not stop him loving her deeply and wanting to find another resolution of the crisis, rather than Pete Tyler having to die twice. Ecclestone's doctor has always been absorbing to watch, but here one warms to his charismatic portrayal more than in any other episode hitherto. Two particular moments stand out - the depth in Ecclestone's eyes and his desire to help Rose when she asks to go back to the accident a second time, and his worry as he knows the dangers of interfering with history. Secondly, his care for the marrying couple, particularly the line "who says you're not important?"

Pete Tyler is a marvellously well written character, played to perfection by Shaun Dingwall. He is totally believable, and we get to know him in considerable detail for just 45 minutes. Endearingly fallible, it's a splendid touch that he of all the 1987 characters understands quickest what is going on - suggesting that, for all his being a failure, Rose's dad has passed his ability to accept new, perhaps wild ideas to his daughter.

The relationships are magnificently realised in this story, for example Rose's realisation that her parents weren't happy and that Pete was far from exemplary, both in marital and in business terms. Billie Piper has repeatedly surprised throughout this season with the quality of her acting, and in "Father's Day" she is quite superb, being totally believable to the point where I almost forgot this tale was fictional.

The special effects are stunningly impressive, particularly in the realisation of the Reapers, and in the hit-and-run car continually appearing and disappearing. They are almost incidental to the story, however, which is, quite simply, as moving a small-scale character-driven piece of drama as I have seen in years.

The script wrung every opportunity for emotional tension out of the idea, whilst actually managing to make sense with surprisingly few holes. I liked it that the Doctor explains that he can't go back and save his own people, presumably because of time paradoxes, which is a question a few of us have raised from the earlier episodes.

Gut-wrenching human drama; the unremitting tension of the characters being trapped in a church under siege from ruthless alien creatures that cannot be reasoned with; magnificent acting all round; a heroic Doctor to believe in; tremendous characterisation; superb incidental music throughout; and intelligent, thought provoking insights into the way we view our history, why certain things cannot be changed, whilst showing what is worth fighting for.

For a single 45 minute episode to encompass so much is a towering achievement - can it get any better than this?

One of fandom's most acclaimed writers finally gets a chance to write a televised Doctor Who story. Surely this is going to be a classic?

Paul Cornell's books have always contained spot-on characterisations, sparkling dialogue, and have packed weighty emotional punches. Father's Day is no different. For all of the above, look no further than the scenes where Pete asks Rose what he's like in the future. Shaun Dingwall and Billie Piper are given the very best material, and they don't let us down in the delivery. The episode is peppered with lovely touches such as the inclusion of Mickey, Pete working out Rose's situation all by himself, and The Doctor's "I'll try and save you" speech to the bride and groom.

I was preparing for the worst when I first saw the pictures of the reapers, and they're very obviously CGI creations, but they're very well-realised and effective ones. The POV shots are creepy, and the abductions from the playground are reminiscent of similarly unsettling scenes in Survival's opening episode.

This episode had all the ingredients of a poll winner, so how does it go so badly wrong?

The faults lie within the actual script. There are countless holes in the plot, and bizarre occurrences which are left unexplained. The reapers had at least two chances to devour The Doctor as he storms back to the TARDIS, yet they don't. Neither do they attack the bride or Mickey. How does the TARDIS interior disappear? Why is there rap on the radio and Alexander Graham Bell on the telephones? Why does the Chevette turn up outside the church? Why does the TARDIS key glow in the church, but not in the TARDIS lock? Indeed, why does it glow at all? How does the TARDIS get into the church - or relocate itself at the end of the episode? How does The Doctor get brought back? And why does Pete's death vanquish the reapers, when history still remains changed?

I promised my better half that this episode would bring a lump to her throat and tears to her eyes. Instead it just gave us both headaches trying to figure out the finer points of the plot. The individual scenes may all be superbly written, acted and directed, but the lack of explanations in the script wrecks the entire production.

What a waste.

6/10 (when it so easily could have been another 10/10).

At last, a win for the single-episode format. A simple story, told simply, 'Father's Day' nevertheless packs a lot in: a half-decent backstory for Rose, top-notch acting (nearly) all round, bags of emotion for those who like a good cry, plus loads of symmetries for the structurally minded. A sense of dreadful inevitability pervades the entire episode: from the moment Rose intervenes to save her father, the end is unavoidable, but waiting for the characters to work everything through was a joy -- in the tearful sense. Best of all, it's a story that actually requires time travel; I particularly appreciated the fact that the demise of the Time Lords has wide-ranging, unexpected repercussions. Even the sound track is, on the whole, kept in check to allow the dialogue to shine.

There are too many highlights to list -- the shock of police box-sized Tardis interior among them -- but I particularly loved the way 'Father's Day' plays with the concept of fiction: Pete is constructed by Jackie as the perfect father, and it's Rose's unwavering belief in this fictional construct which gives Pete the strength to save the day.

It's a pity that the makers got carried away with the cgi -- the reaper monsters were eerily perfect seen circling the church through the stained glass, but more than a touch ridiculous in plain sight. I felt the pace sagged a touch in the middle, bogged down somewhere in the midst of all the group hugs, and Camille Coduri's simplistic portrayal of Jackie continues to be a weak spot.

Though it felt at times like a cross between 'Eastenders' & 'Doctor Who', 'Father's Day' somehow manages to make the mix work, and the simple strength of the ending more than makes up for any shortcomings along the way.

The issue of temporal paradoxes was one that Doctor Who dealt with all too rarely; usually the TARDIS was simply a device for establishing setting, and it was left at that. When it did rear its head, it was treated differently each time: in The Aztecs it was established that history simply couldn't be changed because from the future's point of view your interference has already happened so it's all been factored in. This would seem to be the most logical idea, and is borne out by stories like The Visitation in which the Doctor's involvement results in the great fire of London.

In Day Of The Daleks the Doctor could change history safely as by doing so he was in fact repairing a temporal paradox and generally giving history a bit of a spruce up. City Of Death presented a more standard alternate-timeline theory, while Attack Of The Cybermen told us that to change history would destroy the universe. Now, with Father's Day, changing history results in massive gargoyle like creatures appearing and eating everyone.

Frankly, that one came a bit out of left field.

Maybe I'd underestimated Paul Cornell, but I enjoyed Father's Day a lot more than I thought I would. With such a complex subject it's easy to get bogged down in problems but he subverted this by giving us a character study first, monster story second. In this sense it's slightly disappointing as the Reapers are such superb monsters: not evil, but doing what is necessary to protect the time/space continuum. I must admit though that keeping them in the background increases their menace, and the shots of their silhouettes swooping round outside the staned-glass windows of the church work wonderfully.

As with Dalek Joe Ahearne's directing was excellent, a particularly good example being the washed-out overcast effect used when it seems that the good guys have lost. The shot of the time-looped car going round and round is chilling, and Murray Gold provides one of his best scores for the series.

Now to the most contentious aspect: the Doctor's apparent death. The Doctor's plan fails, and it takes the noble sacrifice of Rose's father to bring him back. Ordinarily this would be fantastic, but in a series where the Doctor seems less and less involved in the resolutions of the stories it seems to be taking it a bit too far.

What this episode is first and foremost though is an emotional journey for Rose. This was something the original series never really got the hang of (sometimes it did though: the Doctor comforting Victoria in The Tomb Of The Cybermen is my all time favourite scene), and this completely thrashes the most emotionally literate episode of the original run, The Green Death in that respect. It makes it even more of a pity that Russel T. Davies, with his smug jokes and less than subtle subtexts is in charge.

Overall then, a 9/10. The least of the three non-RTD scripts we've had so far, but when you consider the brilliance of The Unquiet Dead and Dalek this is hardly a dreadful criticism.