Billy Connolly's Big Send Off, ITV

How amusing is death? When stand-ups fail to get laughs on stage, they call it dying, because the silence is like the grave. When actors laugh when they’re not supposed to on stage or on camera, it’s called corpsing because it kills the scene. They can do birth, marriage, divorce and illness, but death is the one part of the journey a comedian can’t turn into first-person material. Not even Tommy Cooper, who literally died on stage.

That at least is the thinking behind his new documentary, which sends him hunting for jokes in cemeteries and funeral parlours, among undertakers and corpses. The spur was Connolly’s recent diagnoses – with prostate cancer and early-onset Parkinson’s. Greeting mortality as an opportunity, he has embarked on a tour of the death industry in his adoptive America. “It’s only when you take a good look around,” he advised, “that you realise it’s bloody everywhere.”

Most of this first of two instalments of Billy Connolly's Big Send Off was shot in California, with a stopover at a funeral directors convention in Austin where he wandered among the coffins looking for gags. There were visits to a pet cemetery, a repository for human ashes known as a columbarium, to a mosque which also caters for Jews, and he boarded a boat out into a heavily overcast San Francisco Bay, where the last wishes of several deceased seems to have been to have their ashes to be scattered in sight of the Golden Gate with a Glaswegian ex-welder looking on in John Lennon shades.

Along the way Connolly unburdended himself of observations, the odd celebrity anecdote and statistics fed him by researchers. He sat in his or possibly someone else’s kitchen talking about the approach of the grim reaper. He dropped in on Eric Idle, friend and neighbour and author of a never-to-be-staged Broadway spectacular called Death: the Musical (Sample lyric: “First comes denial/then anger and bile/then bargaining, then you’re depressed for a while.”)

Oddly for someone who has never needed a script, there was little of Connolly's fizzing spontaneity. The best joke found him responding to a coffin salesman hymning the lightness of his product, which (without a customer inside) you can apparently lift with one finger. “In case you’ve got no friends to carry our coffin?”

But more often Connolly was finding things funny rather than being funny. And he was bountiful with the truisms. In death as in life there are haves and have nots. Treat death as part of the very day and stop worrying about it. Make the best of it while you’re here - you’re a long time gone. Death, the great leveller, has turned one of the funniest men alive into an ordinary mortal, as platitudinous and clay-footed and unamusing as the rest of us.