Dalek

Once again, the work of a different writer marks a much welcome change of tone and pace for the show.

There were huge expectations for 'Dalek' - the return of the most celebrated of the Doctor's enemies, the middle-season event episode, the promise of a darker, more complex tale.

Incredibly, it delivered.

After the slightly goofy shakiness of 'Aliens of London' and 'World War Three', we were thrown straight into a tighter, more claustrophobic setting in the form of Henry Van Statten's UFO museum, deep in a bunker in Utah. The Doctor and Rose are catapulted into the tale within the first five minutes (after a rather wonderful fan-pleasing moment featuring a Slitheen arm and - brilliantly - the helmet from a classic series Cyberman), giving us over to the episode's real star - the Dalek itself.

There has been huge build-up to this moment - the Doctor's vague references to the Time War which wiped out the Time Lords and was responsible for countless further damage to the Nestenes and Gelth, amongst countless others, have clearly been related to the Daleks.

And the creature's unveling, followed by the Doctor's gobsmacked reaction, which soon turns to venomous hatred, was outstanding. This was not a dumb, clumsy pepperpot which could only yell 'Exterminate', this was a soldier, intelligent, manipulative and incapable of understanding that there was nothing left for it to fight for.

Until, that is, it uses some of Rose's DNA to repower itself (a contrivance which seems sketchy but is entirely forgiveable given the places it takes the story) and sets about wiping out the inhabitants of the bunker.

There were so many superb moments here, not just Doctor Who moments but moments of real, heartfelt drama. Chris Ecclestone, after looking a little unsettled in the previous tale, dives into the script with a vigour and commitment which is entrancing to watch. Here is a Doctor who is not only eccentric and mercurial, he is damaged. He still hurts and hates for what happened to his people. Ecclestone's movement from fear to hatred to anguish to desperation to sympathy is an absolute joy.

Yet, almost unbelievably, it is once again Billie Piper who runs away with much of the episode. She has none of the Doctor's (or, indeed, many of the audience's) history with the Daleks, allowing her to see the wretchedness of its existence and to show it a second's kindness which ultimately saves all their lives and takes the viewer into the real tragedy behind the two races of aliens whose face-off she gets caught in.

Special mention should also go to Nicholas Briggs, who gives the Dalek more depth than any seen before.

It's hard to see how the series could get any better than this. Rob Shearman should certainly be given more episodes to write next season and I can only imagine what such a radical rethinking could do to, say, the Cybermen or The Master.

All this, and a new companion to boot. The Doctor has been back for a few weeks but now, finally, he's even better than before.

And just what is this recurring Bad Wolf reference leading to?