Well-intentioned but hopelessly misjudged

If there is one thing guaranteed to garrotte my goat, it's a glib clip show containing broad assumptions based on spurious evidence and received wisdom. Are You Having a Laugh? was as maddening as these things get.

A broad survey of how television has portrayed and reflected disability, Kate Monaghan's programme began in an age when there was still something called the Central Council for the Care of Cripples and ended (roughly) with Channel 4's Cast Offs, a drama presented as having got pretty much everything right. Well, perhaps, but I'm willing to bet that if somebody makes another survey documentary in 40 years' time, its attitude to the disabled may look appallingly out of touch. Good intentions in these matters rarely exempt you from the disapproval of posterity. When Crossroads included a character in a wheelchair - the gravel-voiced Sandy - they probably felt they were striking a virtuous blow for visibility. Now all we can see is the transparency of the gambit and the fact that the actor was, as Matt Fraser trenchantly put it, "spazzing up". Even today, the nuances are tricky. BBC News got a bit of a hard time here for the self-congratulatory display of Frank Gardiner's wheelchair, though one imagines everyone present would have been even crosser if it had been hidden away. And the pieties about never laughing at disability, but only at attitudes to it, can't be relied on either, since more than one of the disabled performers here made the point that being exempted from ridicule was just as much a discrimination as being singled out for it.

David Walliams narrates a history of disability on TV. It's a slightly directionless tour around the archives from the Spastics Society appeal of the 1960s via Joey Deacon's appearance on Blue Peter to Roy's hysterical abuse of a disabled toilet in The IT Crowd. There are even segments on Heather Mills and Big Brother, although the one about Mills mercifully shows no actual footage of her. Interviewees trying not to say the wrong thing include Mat Fraser, Stephen Merchant, Dom Joly, Ash Atalla and Francesca Martinez.

David Walliams narrates a funny but cringe-making look at how people with disabilities have been portrayed on TV over the years. The first shock is seeing black-and-white clips of people whose lives were improved by something called the Central Council for the Care of Cripples or who were allowed, as the plummy newsreel voiceover man puts it, to work in a factory "alongside normal people". Recent footage makes you wince even more. Like shots of Paralympian Tanni Grey-Thompson winning a sports personality award in 2000 - on a set with a podium inaccessible to her wheelchair. She and an excellent selection of disabled actors and producers reflect on the progress we've made.

Comedians refused to appear on a new BBC2 documentary about how disability is portrayed on TV - because they were scared they would say something offensive. Producer Kate Monaghan said: "A lot of them said no." But she still managed to sign up big names such as David Walliams, Stephen Merchant and Ben Miller for Are You Having a Laugh.

Stephen Merchant: Disability jokes intrinsic to script

Jokes about disability in The Office and Extras were not sprung upon actors, but were "intrinsic to the script", comedian Stephen Merchant has said.

David Walliams narrates a show about the nature of disability in comedy. He motors through from Benny in Crossroads to Francesca Martinez from Extras. If you think you know what it is going to be like from that description, you're exactly right.