It always hurts to see a clever British comedy star forced to conform to a tin-eared Hollywood idea of what a posh Brit should sound like. Russell Brand went through it with the Arthur remake, and now Steve Coogan endures the same thing in this entirely disposable comedy about a super-gay celebrity foodie called Erasmus presenting a cookery show on American TV.

He bickeringly lives in a lifestyle-magazine-type hacienda with his long-suffering partner and producer Paul – in which role Paul Rudd does his best. They are living the dream, kind of, until a tousle-haired kid turns up out of the blue. Bill (Jack Gore) turns out to be Erasmus’s grandson, via a rashly experimental heterosexual hookup ages ago, that Paul knew nothing about until now.

The resulting grownup son is now in jail on drugs charges but he managed to get Bill away before the police showed up, with instructions to look up his granddad in Santa Fe. Yikes! Do you suppose these squabbling selfish gays are going to be furious at first, but then grow to love the kid, and then face a Kramer vs Kramer crisis with the authorities?

Of course, Erasmus could quite plausibly have been Bill’s dad, not granddad, and that would have created a more prominent part for the boy’s mother. Disappointingly, there are no interesting roles for women in this film.

The movie concludes with a rather solemn series of photos of real-life gay couples with their babies, running over the credits, just to show that this film’s heart is in the right place. And so it is, but this means the film is chary of the cynicism or satire that it initially appears to be serving up. There are simply no funny lines here.