OK, first let's just remind ourselves that Doctor Who is a kids' show, and that overanalysing it would be very silly indeed. However, this collection of David Tennant's final four ­adventures has ambitions to give the character more depth. Watching them back-to-back reveals the arc Russell T Davies, in his last stint as head writer and executive producer, was aiming at – one in which the Doctor becomes ­increasingly withdrawn and angst-­ridden as his regeneration looms.

Having jettisoned his assistant, Donna, at the end of the last proper ­series, Tennant's Doctor is essentially taking a supremely confident lap of honour: he's so comfortable in the role, he could probably get away with standing alone in the Tardis reading out the phonebook. Davies is also at the top of his writing game, and each adventure is a rock-solid Doctor Who yarn. If you know somebody who hasn't got the bug yet, this would be the perfect place for them to start.

The opener, The Next Doctor, exemplifies just how right they're getting it. It's a perfect amalgam of snappy drama, effortless comedy and great production values. The Doctor pops up in 1851 London where he bumps into Dervla Kirwan, playing a creepy proto-feminist who's using the cybermen to advance her cause. Visually, it's ­glorious: the ­terrifying climactic scene, in which a steam-driven ­cyberman the size of Big Ben rampages through the city, is something that ­today's eight-year-olds will one day be showing their own kids.

The collection hardly drops the ball, although the climax of the final episode – the one shown on New Year's Day, in which the Doctor revisits all his former companions – may be a tad self-­indulgent. But it reminds you just how great the show has been for the last four years, and just what a tall order Matt Smith has as the new Doctor.

As Davies would no doubt tell you, sometimes there's nothing wrong with embracing your inner kiddy.