EXT. DESERT. DAY.

That didn’t take long. Scene directions never do. And yet to realise it, the producers will have to fork out thousands of dollars, recruit the film crew, the actors, the people who look after the crew and the actors, and the people who organise getting large groups of people into any location indicated in the script, however remote. And then there’ll be the stunt men and women, the catering corps, the tent people, the props department, the wardrobe department, the people who teach the actors hopefully not to fire live rounds at each other. And so it goes on. Most people have left the cinema by the time the last make-up artist has been credited near the bottom of the scroll of honour.

And by the time the scriptwriter’s script has been turned, at eye-watering expense, into the Oscar-winning blockbuster, he or she will be well into their next set of instructions: INT. RESTAURANT. NIGHT. A smatter of small-talk, then segue into EXT. RUNWAY. DAWN and off we go again.

Script writing is not something I’d ever associated with ghost-writing, but then a story arrived in my inbox which simply screamed Film! Oscar season seems a good time to explore what this might involve.

Like most – but not all – of the jobs I’ve taken on over the years, this is a true story. And it’s amazing. As is often the case, the first thing to do is establish the facts, and then tease out the story’s connections, the thread of one thing leading to another without inexplicable gaps. Quite often you don’t spot the important questions until you get to the point in the story where one thing doesn’t connect with the next thing. When you do, there’s often the response: Oh, I didn’t think that was important. You take the answer gratefully and push on with telling the story.

But telling it as a film dramatically different. We had a serious conversation at the start of the process. Yes, the story is great, surprising, amazing. It could be made into a book. But there was something about its epic quality that cried out to be screened. It would have made a great documentary, but there was nobody filming it at the time – though the great global event that it runs parallel to is well documented. So let’s go big, I suggested. Why not? What have we got to lose?

So, that’s what we’ve done. We’re turning a boyhood adventure into what we hope will be a blockbuster. I’ve explained that as it isn’t a documentary, it’s going to have to follow all those ‘Based on a true story’ films in pushing things a bit. This has its consequences.

I’m not someone who likes waiting until all the research is done, every episode identified, and every brick in the narrative wall neatly numbered. I like to know where we’re going, but I also find jumping in at the deep end is a remarkable stimulus to creativity. I felt I needed to get the story started. This entailed a bit of family background. Everyone has a younger sister, don’t they? No they don’t. (I don’t.) She and all her scenes had to go. Actually, the whole opening section had to go. Not exciting enough. EXT. DESERT. NIGHT. is how we start now, and it’s pretty damn exciting.

And it has to get more and more exciting. Jeopardy has to ratchet up, with everything leading to a finale of seemingly insuperable danger and threat, culminating in – well, we all know how these things end. Easy-peasy, you’d think. But no. Screenwriting is a craft, and there are rules. Serious rules. No one tells a novelist how many pages her story should take up, or a biographer for that matter. Poets, the feline strays of literature, can do whatever they like – except when it comes to writing sonnets, of course. But every film script is a sonnet in that there are strict rules about length: it has to be 100 pages long. Martin McDonagh’s The Banshees of Inisherin has been nominated in nine different categories. One of the things he is admired for is his strict adherence to the conventions. His producer, Graham Broadbent, has been quoted as saying, ‘As a producer, a lot of your time is spent in development, redrafting, redrafting, redrafting. Martin just says, “Here you go. Here’s your 100 pages. Do you want to make it?”’

Squeezing a story into 100 pages is tough. You have to be ruthless. Every scene has to be as sharp and as short as you can make it. If you don’t need dialogue, don’t write any. The same goes for characters. If you don’t need them, you need to eliminate them. You have to cut corners, simplify things, speed things up, wrench reality into an all-absorbing story that will hold an audience’s attention for two hours.

It must be an extraordinary experience having that done to your life, and I know with every draft I share, I am pushing my luck. ‘It didn’t happen!’ ‘I know it didn’t happen, but when you’re in a packed cinema surrounded by complete strangers crying their eyes out, even you’ll believe it happened!’

So far, so good.

We haven’t discussed who gives the Oscar acceptance speech, but I guess our roles are obvious: I’ll write it, he’ll deliver it. We’re aiming for 2025. Watch out for it!