Big cause, big but patchy gig. For more than 30 years the Amnesty International benefits have regularly delivered magical moments.

Rowan Atkinson’s classic schoolmaster sketch springs to mind, while in 2006 Russell Brand and Sarah Silverman were both revelations.

This year’s four-hour epic packed in plenty of laughs, if few dizzying heights.

The structure did not help. The absence of a single compere — celebs including Jonathan Ross, Graham Norton, Fearne Cotton and Gok Wan jobshared — meant that things never quite flowed.

Ten-minute sets sufficed on the brutally edited version aired on C4 last night, but they were not ideal on Saturday evening.

Too short for the strong acts, too long for the indifferent ones. Opener Frank Skinner, for example, left everyone wanting more.

His superbly bawdy reflections on middle age proved that while his body might be seizing up, his comedy brain is as agile as ever.

Alan Carr also effectively explored his decaying frame, bemoaning his ailing knees: “I can’t mince, I’ve lost work.”

Other highlights included Australian Tim Minchin’s rudely clever songs and American Kristen Schaal’s engagingly dippy humour.

Shappi Khorsandi was one of the few acts to refer to human rights, saying that there was free speech in her native Iran, though not after you’ve spoken.

Favourite memories? Sean Lock’s swan impression and Jon Culshaw’s dead ringer of Boris “Cripes” Johnson. Eddie Izzard closed with an evolution riff that was funny, if not particularly coherent.

In that sense, he summed up the entire event.