Good Omens on Amazon Prime is a five and one-half hour exercise in schoolboy humour, that is, a brand of humour practised by witty adolescents – not an easy thing to pull off either.

Based on the novel by Neil Gaiman and the late Terry Pratchett, Good Omens does indeed howl away nicely for much of its length. But when the series trots out the usual atheistic nostrums (ignore heaven and hell; it’s our world to fix), it violates the cardinal rule governing schoolboy humour: never get serious.

Here’s the plot. Two angels, heavenly Aziraphale (Michael Sheen, pictured left) and hellish Crowley (David Tennant, right), learn that Armageddon is nigh – 11 days away. The problem? Well, as Crowley says, everything Aziraphale and he have come to enjoy on earth – music, old books and wine – will come to a crashing end, or at least for Aziraphale; all the good authors, composers (“all of the Bachs”, Soli Deo gloria notwithstanding), and wine casks are in hell. And the rumour is that God likes The Sound of Music. (See what I mean about schoolboy humour?) Somehow, they must bring an end to … the End. Actually, Crowley has no intention of doing anything of the kind because he figures the devils can win, but Aziraphale, being a first-class nincompoop, swallows the story pitchfork, line and sinker.