In a film, as in a relationship, there’s usually a definable moment when you know it’s all over. Someone says or does something that’s so preposterous, it takes a moment to sink in. So you start looking around wildly, disbelievingly, hoping you’ve misunderstood, and when you realise you haven’t, the lift shaft plummets in your stomach. Shortly after, that is when you walk out.

I had to be physically restrained from walking out of the Darkest Hour. For those of you haven’t yet seen Joe Wright’s otherwise brilliant Winston Churchill biopic – or indeed read Charles Moore’s equally brilliant Spectator piece on why he refuses to see the film – then, spoiler alert, there is a scene towards the end when, on June 4th 1940, Churchill is en route to the Commons without the faintest idea of what he’s going to say.

So far, so far from believable it’s not even funny. And it gets worse.

Unable to decide...