He has been described as a purveyor of mild-mannered Marxism and the acceptable face of left-wing comedy.

No wonder Jeremy Hardy fits so neatly into those not-quite-as-cosy-as-they-seem Radio 4 shows.

But skilled broadcaster that he is, it is on the live stage that Hardy shows the true breadth of his talent.

One critic astutely described him as being: "One minute lewd, the next blimpish, the next acerbic - he is always one step wide of insult and one ahead of expectation."

Hardy himself is, of course, far more self-effacing. When I asked him what the audience could expect from his show at the Tivioli Theatre in Wimborne tomorrow, he replied. "Oh, Just an old man rambling. There's no structure to my act, it's quite formless, really."

I point out that he's selling himself short. That perhaps the formlessness is offset by an intuitive comic skill honed by more than 20 years of experience.

Hardy concedes this may have something to do with his ongoing ability to find employment but adds: "I'm never really sure where my act is going. You certainly can't accuse it of being polished."

He says he sees it as a work in progress. "I don't conceive a new show, write it and go and do it, I just keep topping up the act, taking out old bits, putting new bits back in, taking out new bits putting old bits back in."

Whatever the mechanics, it works. However, it's intriguing that Hardy, at the age of 46, automatically casts himself as an "old man".

He admits that age is something he thinks about a lot. He's aware that he works in a business where new, younger talent is always snapping at his heels.

"Audiences like to see new people and I'm afraid they're not very loyal. Audiences are very fickle, I find. They forget that we have to make a living."

Happily Hardy continues to make a very good living and he's even unwittingly found his own antidote to the ageing process: working with older people.

He's about to embark on a national live tour of the long-running radio show I'm Sorry I Haven't a Clue.

Not only is he the youngest member of the panel but the chairman Humphrey Lyttelton is well into his 80s.

"It's great, I'm like the new bug even though I've been with them for about 12 years. It's quite a luxury, it really is like I'm the honoured guest. What's even better, though, is that Humphrey's 40 years older than me. It's nice be the young one again."