Who are they trying to kid? Anderson hasn't appeared in court for almost five years, something he acknowledges when a legal point emerges during the programme: "The little bit about criminal law I know is from watching television in the afternoon now that I'm not at work". Was he a good lawyer? "I was reasonably unlucky in my legal career. In the same way, I've been very lucky in television." It's a typically Andersonesque reply. Balanced, genial, maddening if you're interviewing him. "Notwithstanding such and such," he'll say. Or, "that much having been admitted". He may not still practise, but he speaks like a barrister.
Anderson is notorious for not discussing his private life (his wife, Jane, is an Aids specialist; they have three children). Nor does he enjoy talking politics. As someone who enjoys grilling MPs, he likes to keep his opinions to himself. At least, in interviews.
The Times diary once told a story about a dinner that Anderson shared with Virginia Bottomley, then Health Secretary. Bottomley left to go and vote. At which point Anderson, infuriated by the proposed closure of Bart's, where his wife once worked, exploded: "If you want treatment you should wrap yourself in a fur coat and ask for Rolf Harris". Bottomley apparently returned to find him still going.
At school - Harrow County Grammar - he was friends with Michael Portillo. They were part of a group (including Geoffrey Perkins, now head of BBC comedy) known as the "A2 mafia". "Portillo was the ring leader," a contemporary said recently. "It was a shady, despicable clique - the worst kind of nasty, bitchy bunch." Were they really that bad? "I suppose any little group at school is a smug lot," Anderson says deadpan. "I hope I was the least smug and most pleasant."
Matthew Francis, director of Greenwich Theatre, was a schoolfriend. "Clive was very funny, very sunny, very quick," he remembers. "He always gave me the impression of being slightly shy. He had girlfriends, but was never flamboyant. "
From past interviews, it's hard to work out whether he is still matey with Portillo. Has he been a bit shifty about his old friend? "I'm perfectly frank about my relationship with Michael," he giggles. "We've drifted a bit. Now, if I see him once a year, I think I'd be overstating it."
Did he watch Portillo lose his seat on election night? "Yes, I did. It was an odd moment, wasn't it?" He giggles again, infectiously. "I haven't persuaded him to be a guest on my programme yet, so I want to withhold any remarks I might make until then. It's the same with Tony Blair. I knew him when he was a barrister. I know him now. But I can't get him to come on." Both Blair and Portillo were guests at Anderson's 40th birthday bash.
In the travel documentaries Anderson made for the BBC, he never looked entirely convincing. What he will be remembered for, though, is keeping the chat-show genre alive almost single-handedly. His finest barbs still amuse. Like when David Frost informed him that, "One of the great sadnesses in my life is I never saved up the Air Miles in my early years. I'd have a free trip to Pluto by now." "It's one of the great sadnesses in all our lives," Anderson shot back. Richard Branson tipped a glass of water over him: "I'm used to that, I've flown Virgin Atlantic," he retorted. What would he ask himself? He pauses momentarily. "Not so clever when you're answering the questions, are you?"
But the wit shouldn't disguise a less flashy talent: he is skilled at asking questions it would be easier not to. "For good or ill, the way I do interviews is close to the way anyone cross-examines in court." Which is probably why his talk show has endured. He fits the format because, "the way I talk on a chat show is only a heightened version of the way I talk in real life."
Looks-wise, Anderson is less well-adapted to Planet Chat. He fidgets. His neck is a shrug that went wrong. He gets called recessive-eyed and Teflon-headed. These remarks must hurt? "Yes, it's cruel," he says, not sounding too distraught. "I do rely on the following: television doesn't always bring out the best in people. I'm not quite as short as I look on TV, I'm not quite as fat, and I'm not quite as bald. There must be some people who like the look of me. Some people with very unusual requirements."
He says it will be hard to top his most-satisfying interview, with Mikhail Gorbachev. Maybe the only way forward is to reinvent himself as a "serious" TV personality? Recently, he appeared on Question Time. If, God forbid, David Dimbleby fell under a bus, would he fill the gap? "Mmmmm, yes - though I'm not applying. For a start, I'm not called Dimbleby, which I think is a necessity to present a serious BBC programme."
He now thinks it unlikely he'll return to the law. But, ever a pessimist, he's convinced each series will be the last. What do you do when you've had two careers already and you're only 44? He'd like to embark on a third - writing - he says, in the way that most people say they'd like to go on holiday. "Are you happy?" I ask. "I'm not happy-go-lucky," he says. "Generally, I'm aware of the sadnesses of the world. But, then again, I might be joking. Who knows?"
Clive Anderson presents `Hypotheticals: Making Advances' on Fri at 7pm on BBC2;
`Whose Line is it Anyway?' is on Thur at 10pm on C4
1950s: A star is born in Middlesex to the son of a "stern" Scottish bank manager. It's the kind of family where he's sent for elocution lessons, aged 8.
1960s: Attends Harrow County Grammar School. Going on to read law at Cambridge, he becomes president of Footlights and friends with Mel Smith, Griff Rhys Jones and Douglas Adams. Typical Anderson joke: "I have a friend who's in oil in a small way... he's a sardine."
1970s: Clive hits the Bar: "Being in the criminal courts for 15 years is not a great way to see the best of humanity," he reflected later. "I'm always aware of what other motives someone might have."
1980s: Anderson supplements the day job by writing scripts and acting as a TV warm-up man. He gets a break in radio, which leads to a job as host of the impro show, Whose Line Is It Anyway? In 1989, is given his own Channel 4 chat-show, Clive Anderson Talks Back. "The thing about him is the speed," says producer Dan Patterson. "I've never met anyone of such lightning quickness."
1990s: Career lift-off. The chat show eventually moves to BBC, and the roving brief gets his own travel series: Our Man In... His estimated earnings are now pounds 30,000 per show. Time to get serious?