On Chain Reaction (Radio 4), Alastair Campbell was also recalling recent history. He was very comfortable discussing his soft-porn writings ("a mixture of stuff you'd done and stuff you wished you'd done), his drinking, his "crack-up" and his depression. When he was appointed as Tony Blair's press spokesman in 1994, he said, they had a bet as to which paper would dredge up which bit of his past first. "It was the News of the World, on the porn, eight minutes after the press release went out."

Eddie Izzard is never off the wireless lately. Last week he was interviewed by Frank Skinner, now he's quizzing Alistair Campbell, once chief spin doctor to Tony Blair and terror of the BBC, now more of a wandering minstrel. Izzard starts off with how the Clan Campbell got its appalling reputation, what it was like for a Campbell to grow upin Keighley, what differentiates a busker from a street entertainer, being a swot, going to Cambridge, trying his hand at pornography, having a nervous breakdown. I think I've heard most of this before. Too often.

Just time to revise my view on Radio 4's Chain Reaction. This week's interview with Eddie Izzard by Frank Skinner was excellent: funny and revealing. You forget that Skinner used to have a chat show. Though I'm not saying it should be brought back, mind.

And now let's recommend another comedy series that is hardly in the full blush of youth: Chain Reaction (Radio 4, Wednesdays, 6.30pm), which this week will be half-way through its second series. The format is simple: the interviewee in the first programme becomes the interviewer in the next, and so on until the interviewer in the first becomes the interviewee in the sixth. The conversation may range freely, but always starts from the same point - the comedic style of the interviewee. It works best when both are stand-ups - they're good at being automatically funny - and the series reached a peak last week, when Dave Gorman interviewed Frank Skinner.

It's easy to dislike Skinner. There's the football, the laddishness, the swearing, the pornographic stage show. Listening to Chain Reaction, though, it was just as easy to like him. This is one charming guy, as honest when discussing his financial troubles - his life savings took a bit of a hammering when the American bank in which they were residing went under - as he is frank (it's the only word) about his sex life. It takes a very un-laddish lad to admit that the disadvantage to three-in-a-bed sex is the occasional clash of heads and the constant fear, on the part of the man, that the women are whispering about him, and giggling.

He can also tell a story about his straitened upbringing without coming over all Angela's Ashes. Yes, it took some time for the Skinner family's council house to acquire an inside toilet, but when they did his father was not impressed. A toilet inside the house? That sounded unhygienic. And as for the bath, well, the young Skinner bathed only once or twice a year. "Why should I? I didn't have a sex life at the time." Tomorrow's programme is even better - Skinner interviews Eddie Izzard.

Comedy probably divides opinion like nothing else - what one generation finds rib-tickling, another can find unfunny, even distasteful. Having started his stand-up career in Edinburgh back in 1987, some might consider Frank Skinner a somewhat fossilised funster now compared to the new, young names on today's circuit. But, during Radio 4's Chain Reaction, it's clear that fellow, albeit very different, comedian and guest interviewer, Dave Gorman, has a healthy respect for the banjo-playing Brummie as he reflects on his love of live performance, football and even outdoor toilets. Dubbed a comedian of the lad culture age, Skinner admits success could have easily made him complacent now he's hit middle age and got money in the bank, but seems determined to try new avenues of comedy.

Growing up, he reveals, he wanted to be a cowboy, footballer or a pop star. Having recently rediscovered his musical bent, all he needs now is to adapt an old George Formby song and he could be storming the charts again, like when Three Lions hit number one and made him a truly household name. The next Chain Reaction sees Skinner swap chairs and interview Eddie Izzard - comedic chalk and cheese if ever there was, not least in wardrobe and make-up departments.

Last week's interviewee, Dave Gorman, becomes this week's interviewer as he poses the questions to Frank Skinner. In fact, we hear more of Gorman's mirthful laugh than we do of his words, as Skinner talks us through his part-glamorous, part-filthy career in comedy. There are the usual tales of his experiences in a threesome, but a surprising insight on how he dissects every word about his performances. There's also a lovely story about growing up in a house with an outside toilet - David Baddiel is convinced that his friend Frank was raised in the 1920s.

And a few other notes, both low and high: why no women on Chain Reaction (R4), where public figures (usually comedians) get to interview other public figures (usually comedians)? Yes, we've had Catherine Tate and Arabella Weir, but we're six series in now. This week's programme, the first in the new batch, began with Robert Llewellyn interviewing Dave Gorman. Gorman was far too pleased with himself; but then, that's the nature of this self-congratulatory series. You may as well call it Blowing Smoke.

Robert Llewellyn, of Scrapheap Challenge, interviews Dave Gorman, comedian, of Are You Dave Gorman? Is he obsessive? asks Llewellyn. Suppose so, says Gorman, but real obsessions make good shows. Is it all a bit egotistical? Gorman asks himself, then answers it, saying not really. The Daves in his adventures are alter egos. He started off as an ordinary stand-up with jokes, was inspired by Ian Dury's song Reasons to Be Cheerful to branch out into real-life jaunts. Who will Gorman interview next week? If anyone's still listening by then...

Dave Gorman on Twitter

Video clip in which Robert Llewellyn asks Dave Gorman about his experiences using social media tools.