His style just doesn't date. Surreal musings on sausage-meat and retro-gags about Slade and The A-Team will be here today and gone tomorrow. But Connolly - like David Attenborough's safari suits - just carries on regardless of the prevailing winds in fashion. He makes no attempt to be PC, blithely laughing about 'taboo' subjects such as Stephen Milligan, Fred West, Alzheimer's and the handicapped. At the Hammersmith Apollo, this was his considered assessment of the difference between the sexes: 'Women can hold in a fart and men can't' He even made a joke of his sometimes Neanderthal attitudes, saying that although he's never slept with a man, 'I fully intend to. Never let it be said I'm not politically correct' (to loud applause).
It's not that he tells great gags (although some of his one-liners - a scrotum is like 'the last chicken in Sainsbury's' - would not be kicked out of bed by lesser stand-ups). Rather, he inundates you with this great big, swamping personality, wave upon wave of Connolly lapping you into laughter. The experience leaves you happily drained, like a Cross Channel swimmer sprawled on the beach at Calais.
He has a keen eye for detail - reflecting on the beige colour of strawberry jam melting into a crumpet - and uses language of rare vividity; coitus interruptus is like someone saying to you: 'Here, have a box of Quality Street, eat all the papers, and give me all the sweeties back.' A psychiatrist could have a field-day with the free associations that drive the show. In one dazzlingly illogical sequence, he digressed from Catholicism to Calvinism to Switzerland to Toblerone to scones to lame ship-workers (don't ask me how).
Connolly enjoys a wonderful relationship with the audience - except for those ill-advised souls requiring a pit-stop (he raged at one unfortunate trying to sneak out at the climactic point of a routine, 'I'm talking about coming and you're going'). At one stage, audience laughter made him corpse, and he adopted mock-schoolmasterly tones to tick them off: 'I can see some homework being given out.'
So let's forget about the Fergie factor. What other contemporary stand-up could keep a packed Hammersmith Apollo gripped for more than two and a half hours without a break?
Billy Connolly is at the Hammersmith Apollo tonight & 23-28 May (Box office: 081 741 4868).