There are some films that you know are probably very good but you are prevented from going to them by a deep inertia caused by fear. You are unwilling to expose yourself to a meditation on a possible state of being which is so appalling that you go rigid at the very thought. And this state of being could be just round the corner for any one of us. It is not a rare condition. It could be Alzheimer’s or a stroke or a crippling accident or sheer senility.

Whether you read Poe or Lovecroft or Crowley or Kafka, you are aware that the pit is a form of interment and the pendulum continues to tick. Being buried alive has a pedigree of crazed fear that must reach back to the dawn of sentience. To be still alive and yet incapable of drawing attention to your flesh and blood, your neurally networked reality seems an extreme too far.

It is this jumble of gibbering horror which lies beneath the urbane decision not to go and see The Diving Bell and the Butterfly. Only the title seems wrong. It is a little too whimsical despite the film’s extraordinary range of emotional enquiry from the crudely sardonic to hardly bearable pathos.

The story, if you are unaware of it, is about a man who has a stroke which severs, effectively, the upper cortex from the rest of the brain. In awful brief, he is left with an eyelid that he can mobilise. We, the audience, communicate with this eyelid and when it rises we can enter his thoughts, memories, feelings and his commentary upon his condition. We eventually see him write a book about what has happened to him as his remarkable nurse calls out letters of the alphabet and he gives a single blink for the one she must choose. He died a few days after the book was published.

The strong beam of light in this film, the searchlight that almost blinds its two-eyed mobile watchers, is this. Existence is unbelievably precious. We only value our consciousness when we are about to be deprived of it through death or are bereft of it through desperate circumstance. We are alive. It’s a thing of wonder. We must exploit it to the full, just as the great hero on which the film is based did, in the terrible circumstances in which he found himself.

It is a film which is magnificently life-affirming.