Has Billy Connolly lost his mojo?

He's still on tour at 69, but Britain's 'greatest stand-up' is turning into a cantankerous and unpredictable diva, says Simmy Richman

Last week, Billy Connolly was voted the UK's 'most influential stand-up of all time'

In 2007 and 2010 he came top of Channel 4's list of the 100 Greatest Stand-Up Comedians. Last week, he was voted the UK's "most influential stand-up of all time" in a poll of his fellow comedians. The public and his peers are agreed: Billy Connolly is a master of his craft; the best there is. As such, you'd expect him – aged 69 and with more than 40 years' experience under his beard – to be able to handle the odd bit of audience banter. But the comedian has "been heckled off stage for [the] second time in a week" on his current tour and has left disgruntled audience members saying things such as: "People pay hard-earned money to see these shows ... he's a disgrace walking off. What a diva."

Connolly used to have a way with such interruptions. "Did your mother never tell you not to drink on an empty head?" was one classic. "Don't tell me how to do my job. I don't come to your workplace and tell you how to sweep up" another. Such putdowns were not to be heard recently in Scarborough, where an indecipherable yell was enough to see the stand-up curtail his act and leave the stage without so much as a "Thanks for coming. Good night." Witnesses at the Blackpool show say that one person shouted "Wildebeest" (in reference to one of Connolly's classic routines), while another yelled "You're shite, Billy". Either way, Connolly muttered "I'm out of here" and left, mid-gag.

Whatever happened to the Big Yin? Has he – fatal for a beloved stand-up comedian – lost his sense of humour? On the subject of hecklers, it would appear he has. He recently said: "I loathe hecklers. I haven't got a good syllable to say about [them]. When you come out of the club circuit and into the concert hall, they should be gone. There's an element of manners that should tell you that the ticket is dear and it's a different venue. People have had a bath to come here so sit down, shut up and listen."

The most telling part of that statement is surely Connolly's use of the words "concert hall". Because while the venues have undoubtedly changed since he started out, even comedy shows in cavernous arenas have a certain anything-can-happen energy crucial to the atmosphere. "Sit down, shut up and listen"? That may be an appropriate instruction for a night at the opera, but would the likes of Michael McIntyre, Peter Kay or Bill Bailey ever demand that of their audience?

So what has turned this son of the Glasgow shipyards into such a cantankerous and unpredictable live performer? There are various theories but all seem to point to a turning point around the mid-1980s. Before then, he had shambled his way charmingly through a musical career with the Humblebums that in the early 1970s saw him leave the music to his partner Gerry Rafferty (exasperated that Connolly's between-song banter lasted longer than the songs) while Connolly concentrated on the comedy.

His breakthrough came in 1975 with an appearance on the BBC's Parkinson. One joke about a bottom later, and he was a national treasure, a friend of the show's host and on his way to being the guest with the record number of appearances on that chat show.

The following decade cemented his reputation but also saw upheaval in his private life. He split with his first wife in the early 1980s, won custody of their two children and moved in with the comedian Pamela Stephenson, an event that he says "didn't change me, it saved me. I was on a downward spiral and enjoying every second of it." But giving up the booze, the woman who had supported him through the lean years and his home in Scotland must have had some effect, and though Stephenson undoubtedly rescued Connolly from oblivion, she also took his private life in a different, rather more jet-setting "celebrity couple" direction.

So what happened to the Big Yin? Other answers can possibly be found on his own website and in his own words. There, in a blog post that reads like a catch-all response to criticisms real and imagined, Connolly writes about trying to reconcile his working-class upbringing with his current lifestyle. "Once you become successful," he writes, "people know where you live, the type of house you live in, the kind of car you drive, the clothes you wear, and so it would be patronising to go and talk like a welder. Welding's a mystery to me now. You can't go back, your life changes every day."

He wants to keep it real, but if he keeps it too real, he runs the risk of alienating anyone who has not made a film with Judi Dench, been paid to trike around America, did not get invited to the wedding of Prince Edward and Sophie Rhys-Jones, has not lived in LA for 14 years, and does not own a 120ft yacht and homes in Malta, New York and Aberdeenshire.

There is also the issue of his age. Bruce Dessau, comedy critic of the Evening Standard, says: "I think there are certain challenges comedians face as they get old: stand-up is intellectually demanding. To follow a line of thought on stage is tough after middle age and particularly with Connolly's style, because he doesn't use a script. When I saw him at the Apollo last time he appeared in London he noticeably digressed and lost his train of thought, more so than in recent years. However it may have been jet lag – he had just arrived from America. Also, he's still doing the same length of shows and tours that he was doing 10 to 15 years ago, so he must enjoy what he does."

"I always saw myself working till I was old," Connolly writes on his blog. "I thought that's what comedians did and I still feel they should. When people ask me why I'm still doing it, I say because it's my job; they don't say to painters, you must have a few bob now, why are you still doing it? The trouble is that you spend the money. I spend an awful lot of money living this funny lifestyle because it makes me very happy and it makes my family all jolly and happy. So I'll keep doing it until I die, or until people get fed up with me or something."

So why should people get fed up with him? There are at least three reasons in that paragraph alone. One: when he refers to "painters", he is clearly not talking about the types who decorate your house. Two: he spends a lot of money not on a "funny" lifestyle, but on exactly the kind of empty pursuits we abhor in those working in the financial sector (yachting, triking, buying property). Three, that toe-curling "all jolly and happy" family. Well, woop-di-doo.

Later, to highlight the schism in his character, Connolly writes about standing "for freedom and the things I really believe in, the things I believed in when I was a hippy, and I still believe in now". Reviewing Connolly for this paper in 2010, I went with an open mind and open notebook. I was amazed to discover that almost every punchline consisted solely of the words "fuck", "fucker" or "fuck you", and the story he spent longest on was a tale about how annoying life is when the butler in your hotel penthouse suite won't leave you alone. As all around me laughed, almost as heartily as Connolly himself, I left feeling as if it was I who had the problem.

Whatever happened to the Big Yin? He is trapped between the person he still believes himself to be and the life he actually lives. He is flattered by the adulation (however much he pretends to ignore it) and is largely unchallenged by playing show after show to drunken crowds made up entirely of the converted. Blackpool, Scarborough, Nottingham, Bristol, Ipswich, Southend-on-Sea ... The truth is that he could play to as many people over five nights at the 02 Arena. But, then, that just wouldn't be a Billy Connolly-type thing to do, now would it? So he'll just keep doing it until he dies, or until people get fed up with him or something.