I’d argue that it’s impossible to write a novel in the 21st-century without thinking in terms of how the action and dialogue would look and sound when adapted into a television series or Hollywood film. Having said that, you might prefer that your sensitive writing be turned into a radio or stage play, or filmed by a European director as they’d show the subtleties of characterisation and not swamp things in computer-generated special effects.

When I’ve written my short stories, novellas and novels, I’ve more often visualised real people I’ve known rather than famous actors. For instance, a recurring character in my Cornish Detective series is a forensic pathologist called CC, and she’s an amalgam of various earthy country doctors and veterinarians I’ve met, along with a female psychologist I once knew, a survivor of Auschwitz, who’d seen the worst of human nature.

Unusually, I’ve imagined my detective protagonist, (who is the son of a sheep farmer), to look like one of the presenters of a long-running British television series called Countryfile. Adam Henson is a farmer, and his laid-back mannerisms appear in my fictional detective Inspector Neil Kettle. My protagonist has a way of lulling whoever he’s questioning into a false sense of security, before jumping in with a killer punch.

I also remembered the appearance and behaviour of a Swedish actor, called Rolf Lassgård, when writing a novella about a man who escorts his wife to the Dignitas clinic for an assisted suicide, and how he rebuilds his life at the age of 60. Lassgård is probably best known for playing Kurt Wallander in one of the television adaptations of Henning Mankell’s detective novels.

The casting of movies is critical to their commercial success but doesn’t always follow how the main characters were described in the novel. The worst recent example of this is diminutive Tom Cruise playing man-mountain Jack Reacher in two film versions of Lee Child’s novels.

Some adaptations get the casting just right. The BBC’s second attempt at interpreting Winston Graham’s Poldark novels, first filmed in the 1970s, is a joy to watch as much for the appearance of the actors, as the scenery and the historical accuracy of the action, even if some of the actors’ attempts at a Cornish accent are a bit shit!

Who would you have to play your characters?

Did you envisage a particular actor as you wrote? Was it their physical appearance or their mannerisms that influenced your writing?