David Walliams: Doing comedy forever would get boring

David Walliams speaks to Metro about his work for Sport Relief, having Michael Caine as a fan and kissing Will Young on Parkinson.

While some comedians are lionised after they've stopped appearing on TV, others are quietly forgotten. Nicholas Parsons spends more than Just a Minute with Paul Merton recalling his partnership with one of the latter - Arthur Haynes. Viewers of a certain age will recall the partnership that pulled huge audiences to ITV in the 1950s and 60s. It's the comedy of a simpler, slower age; Parsons remembers how depicting a vicar in a sketch was considered disrespectful. There's nostalgia and curiosity value, not least with a priceless archive interview with writer Johnny Speight. Plus, rewarding glimpses of Wendy Richard, Patricia Hayes, Michael Caine and the Rolling Stones.

On paper, The Trip sounds bloody awful: a cosy, luvvie giant in-joke for Steve Coogan and Rob Brydon, showing off their impressions and them eating ridiculously fancy meals. So why is it so completely brilliant? "It's not about the destination, it's the journey," as 'Steve' described his refusal to use satnav, but referring also, surely, to the incidental banter and bickering between them which is gradually revealing their true selves. Or 'true selves'.

And it's also hilarious: their Michael Caine-off, "we rise at dawn-ish" and last night's ABBA duet may soon replace Alan Partridge's most quotable lines as the things fans greet Steve Coogan with. Which will be some small compensation for him still not being able to do Rob's "I'm a small man in a box" voice.

All anyone really wants from Steve Coogan is Alan Partridge. And the fact that he knows it, that Norwich's finest swings like a comedy albatross around his neck, underpins the arch air of knowing antagonism he brings to The Trip (BBC2). Here's an anti-comedy if ever there was one.

Featuring Coogan and Rob Brydon playing heightened versions of themselves (their description), The Trip wilfully blurs fact and fiction as this mismatched pair, Brydon's innate amiability crossing verbal swords with Coogan's surly ego, set off on a restaurant review tour of the rural north of England on behalf of a Sunday magazine. It's a perfect set-up, egotistical and pointless, given neither of them knows much about food, which fuels a subtle meander around the oxbow lake of celebrity ego.

Coogan brutally sends up his image with a performance that's so deeply dislikeable you end up admiring his ability to be so sublimely cussed.

'I don't want to do British TV - I want to do films, good films,' he whines to his agent on the phone and, even though you know it's an exercise in fiction and not reality TV, it does feel, well, real.

It's a bumpy trip and no mistake. The laughs are of the dark and despairing kind, built mainly around the pair of them sat at a restaurant table battering each other with impressions, like Ultimate Cage Fighter played out by the voices of Michael Caine and Anthony Hopkins. It's a send-up but it's tongue-in-spleen rather than tongue-in-cheek.

There's a slightly irksome air of self-congratulation but it's hard to take against a show where Coogan chooses Joy Division's Atmosphere ('don't walk away... in silence') as the perfect soundtrack for cruising through the verdant English landscape. Makes a change from The Lark Ascending, that's for sure.