The Lesson is a literary thriller that is occasionally heavy-handed but also menacingly entertaining, plus you get Richard E. Grant in his full pomp. That said, when do you not get Richard E. Grant in his full pomp? Has anyone ever seen him at 50 per cent pomp? Has anyone ever come out of the cinema thinking: ‘I wish Richard E. Grant had given it more?’ The monstrous character is his speciality and he is deliciously, marvellously, full-on monstrous here.

Written by Alex MacKeith and directed by Alice Troughton, The Lesson is very self-aware, always delivering little winks to the audience. It is divided into chapters. It is particularly interested in endings. ‘What makes an ending?’ someone will ask, and by the end you will know. It opens with ‘Prologue’ and a young fella, Liam Somers (Daryl McCormack), being interviewed about his book on stage. The novel, we’re told, tells the story of ‘a fading patriarch presiding over his grief-stricken family’, and what, asks the interviewer, was his inspiration?

We spool back in time to Liam as a fresh English graduate and aspiring writer arriving at the country home of J.M. Sinclair (Grant), Britain’s greatest living novelist, apparently, and he’s certainly done all right for himself. The house is glorious: there’s an ornamental garden, a Monet-style lake, a butler and maids and so on. (Do literary novelists make that kind of money? Maybe he does tie-ins with Jamie Oliver?) His wife Hélène (Julie Delpy) is a cold, enigmatic art curator; there’s a pale, taciturn son, Bertie (Stephen McMillan), who is about to sit his Oxford University entrance exam. Liam has been hired as his tutor. There was another son, Felix, who died but no one talks about him. Until they do.

The atmosphere is strained to say the least, and there is a note of dread from the off. You think you’ve endured stressful family dinners? You should pitch up at the Sinclairs’ is all I’ll say, and if J.M. chooses to play Rachmaninov in the background, don’t argue. Liam worshipped J.M. but soon the scales drop. He realises he’s vain, pompous, a bully and possibly washed up. He hasn’t published anything for so long that his fans think he’s retired. But what’s this? He’s about to finish a new novel? We hear Sinclair’s advice to would-be writers: ‘Good writers borrow, great writers steal.’ (Chekhov, we see the gun.) Secrets are uncovered, jealousies emerge. Conveniently Liam’s guest quarters look directly into the main house where he can see J.M. and Hélène being intimate – draw the curtains, boy! – and when she sees him watching, and smiles, you know he’s in for it now. (Run, boy, run!)

There are clichés – does the world need another dead-other-child scenario? – and the metaphors are unsubtle. The rhododendron tree in the garden, Bertie tells us, stands alone because if any other plant comes near it will ‘strangle the roots’. Hm, I wonder who that could be about? But the film maintains tension throughout and McCormack, who was splendid in Good Luck To You, Leo Grande, is splendid here, perfectly capturing Liam’s charm and guilelessness before it curdles into vengefulness.

As for Grant, I don’t think there is a morsel of scenery he doesn’t chew – he’s probably still picking bits out of his teeth – but that’s his gift to the world, surely. The ending is, in fact, preposterous but that’s an in-joke, I think, about endings and it’s better than an ending that’s boring. Like this one.