Four episodes in, and the ninth Doctor has shown us the present, the future and, last week, the past. In this instalment, we return to present day Earth, and the Doctor’s companion Rose is taken home. Little does she realise, though, she’s been away for quite a bit longer than she thought …

“Aliens of London” is the first of this new season’s trio of two-part stories, and presents us with a traditional end-of-episode cliffhanger for the first time. The last time the show utilised this format was an incredible 20 years ago during Colin Baker’s run, and it is probably safe to say it wasn’t an entirely successful experiment. So far, Doctor Who 2005 has rattled along at a breakneck pace, with the first episode in particular barely giving viewers time to blink. Episodes four and five however, offer the opportunity to tell a broader, more intricate story that has a little more time to breathe. Does it succeed? Well, yes and no to be honest.

Russell T Davies’ third script this year is set firmly in the world of “Rose” although the manic pacing of that episode is toned down here. “Aliens of London” is the weakest of the series so far, but to be fair it is difficult to judge the story in isolation without the benefit of having seen the second part. “World War Three” next week promises to tie up all the themes that are set in motion here. A major problem with this edition, though, is it feels like there is a distinct lack of tension or suspense.

The ninth Doctor continues to be a difficult character to pin down. On the one hand, he is warm and friendly towards Rose, but on the other he displays a childish, and even petulant, attitude towards Mickey. For whatever reason, the Doctor seems to have taken an instant dislike to the character. More like a 10 than a 900 year-old at times, the Doctor deliberately tries to wind Mickey up by getting his name wrong. The boy has done nothing bad or unpleasant, so it is surprising to see our favourite Time Lord behaving in the way that he does.

Christopher Eccleston appears to relish playing this Doctor, despite the fact we now know that thoughts of only doing one season were probably in his mind while making the series. This Doctor can be deadly serious, pensive, commanding and heroic, although at times he does have a tendency to come across a bit Marlon Dingle-like with his frequent bouts of grinning. Other than the regular cast, a number of the actors appear to be playing this episode firmly for laughs. Rupert Vansittart as General Asquith and Penelope Wilton as Harriet are good, but Annette Badland, David Verrey appear to think they are in a sitcom for some reason.

Like “Rose” before it, the episode is a fine example of the way the new series is prepared to treat companions, and how differently it’s done compared to “classic” Doctor Who. We get to see family life at its closest: Rose’s mother Jackie returns as well as Mickey. Due to the calmer, less hectic nature of a two-art story we are able to observe more deeply the relationship between the Doctor’s sidekick and those closest to her. Having established a campaign to find her missing daughter, Jackie wants her to stay and not go off again. Rose, however, discovers the pull of a life she is familiar with is not strong enough to keep her in London. Accidentally meeting the Doctor in the basement of Henriks store has caused her to re-evaluate everything, and the world of adventure he can offer outweighs even her mother and boyfriend. This topic was very firmly embedded in the opening episode and Davies’ builds on it here.

The alien Slitheen are the villains this week and are very odd creatures about which we know little for the time being. Secretive and deceptive, they have apparently been lurking somewhere on Earth for quite a while. A combination of people in rubber suits and CGI effects, these villains are bizarre to look at, having almost babyish facial features atop grotesque fat bodies. Quite what their masterplan is, we are yet to discover, but given that they have been hiding on the planet it must have been a while in the making. They are obviously highly adept at science, as the bizarre experiment with the augmented pig demonstrates (does anybody else think that the scene where the pig attempts to break free from the morgue cabinet is strangely similar to one in the Doctor Who TV movie?) The wind-passing sequence show the Slitheen can be almost as childish as humans when it comes to bodily functions. Their amusement at their newfound ability will most likely have gone down well with the younger elements of the viewing audience, who after all, are the ones the series is primarily aimed at.

Despite the problems with the storyline there are a number of nice touches on show. The fact that the TARDIS is still quite unpredictable is a welcome nod to the past, and the glowing key was an excellent addition to the mystique of Doctor Who. UNIT got a brief mention too, although it looks as though it is now under American command these days. The visual effects are quite impressive, with the Slitheen spaceship especially good.

Whether you are a dedicated follower of the Doctor’s adventures from way back when, or merely a viewer of Saturday night television who is waiting for the Lottery to come on, Doctor Who now exists for everyone. The stated intention of the BBC was to get some narrative back into the schedule for Saturday evenings, as an antidote to the drip-feed diet of quiz shows that have filled the post-Grandstand slots over recent years. What better series to do that with than Doctor Who?

The team behind the scenes have successfully managed to fuse what enthusiasts used to love about the show with what modern audiences are used to seeing post-1990s. Forget about the things the fans complain about, and forget about excessive continuity. Enjoy the programme for what it is – an enormously pleasurable, and, for the first time in a very long time, incredibly popular piece of entertaining drama.