The Empty Planet.

TV Since the first series of The Sarah Jane Adventures, one of the “motifs” repeated across the stories (other than parents are good) has been the lack of people on the streets or stories occurring in locales that don’t require too many non-speaking extras shuffling about, improvising silent conversation or walking a dog, with entertaining expository reasons from the cast such as “Well, it is a Sunday” or “The fairground closed?” Now finally, we have a story which turns this budgetary weakness into a strength in a way which will no doubt become the model as the license fee is squeezed.

The Empty Planet offers the same bracing images of peopleless streets familiar from the likes of 28 Days Later or the various versions of I Am Legend in which the mass of humanity is just gone and those of us who ironically like people but hate gatherings can fantasise about going to the cinema without being disturbed by the rest of the audience (once we’ve worked out how the projector works), break into the National Archive and see what’s really been covered up under the seventy-year rule and having the run of the expensive food isle in Waitrose. Or is that just me?

True, with just a roof shot of the London skyline to sell the absence, much of the action takes place on the same few empty streets, but as with the best of this franchise, the non-diagetic implication of what’s happening beyond the main characters field of vision can be just as chilling as endless shots of a deserted Trafalgar Square. These are the best scenes in the story, Rani dashing about suburbia to a soundtrack of nothing other than the low hum of the electricity supply showing off her inquisitive nature as she checks her neighbour's houses for signs of life. And what a messy bunch they are.

Except in such narratives, once the main character has twigged that they might be alone, often the scariest notion then is that they aren’t. Luckily for Rani, especially since all she had to defend herself with was in the dull end of tv remote control, that meant Clyde and luckily for us since writer Gareth Roberts replaces the silence with some really good character moments as the kids come to terms with their isolation and also their responsibility to discover what’s been going on despite being the zeppos of the group.

Like Sarah Jane, like the Doctor, like Xander, they’re so caught up on this life that they run towards the danger rather than away from it unless they're told not to and even then. For once, Daniel Anthony and Anjli Mohindra were allowed some meaty scenes (that's two stories on the run) in which their characters considered their place in the world (of the kind usually reserved for Tommy Knight) and what they might mean to each other and they were mostly up to the challenge providing some useful chemistry, Anjli offering her now trademark dreamy doe-eyes.

To an extent it’s a shame that as a kids rather than teen show a plot rather than just puberty has to assert itself; a real format buster would have had the two of them trailing about the streets of London (or Cardiff) coming to terms with the loss of everything, especially their parents, the true horror being that Clyde’s joke about him and Rani being the new Adam and Eve might come to pass with the loss of innocence that follows. Humanity would then have popped back in for some unexplained reason after an hour, along with the disappointing return of their hierarchical place within the family unit or some such.

Not that this necessary plot isn’t entertaining with plenty of moments for us to match our wits with the main characters as we um and aha along with them. Kids who’ve just finished watching the release of the third series were no doubt shouting about Clyde and Rani’s grounding by the Judoon and I was especially pleased with myself when I realised what kind of air, the robots were really thinking of, with its shades of Raymond F. Jones's pulp novel The King of Eolim and Lance Parkin’s Father Time, even if the number of choices isn’t exactly huge.

Following which we were gifted that gorgeous shot of an alien world reminiscent of the Boeshane Peninsula and Gallifrey. If only the budget could stretch to us seeing one of these places for longer than a few seconds. How do these robots fit within that society? Is this a Naboo affair were a small child is the one thought best for high office with Ketchup and Mustard or whatever they’re called as nursemade and coup-repellers? Perhaps if Big Finish’s licenses is relaxed a bit – as is rumoured (I read on the internet) – we’ll be gifted with a ten cd series by way of explanation.

Either way, The Empty Planet is brill entertainment, certainly the best story this series that doesn't feature the Doctor, making the most of the need to give Lis Sladen a holiday. It's also surprisingly interesting in mythology terms; the reactions of Haresh and Prince Gavin almost confirm now that Journey's End and The End of Time have effectively been rebooted out of everyone's memories. Again I ask (because I'm fishing for suggestions) are we to assume that its simply RTD taking advantage of the cracks or feeding into the ongoing main Doctor Who storyline in relation to the silence (whatever that is?).

Next week: That guy who played thingy in whatitsname.