Barry Hines has always been reluctant to sanction a stage adaptation of his novel A Kestrel For a Knave, but he trusts Lawrence Till. The script that Till has prepared for the West Yorkshire Playhouse benefits from the experience he gained with his other adaptations and should have Mr Hines beaming.

Actors called for auditions have talked of being up for the “Colin Welland” part or the “Brian Glover” part. Welland and Glover played teachers in the fondly remembered feature film version but director Natasha Betteridge has cast physical opposites. There are to be no reminders of the film.

A novel in which the principal character, Billy Casper, finds and trains a kestrel does present a problem. Till did try a musical version some years ago in which a kestrel was imagined with music. How will Kes fly in Leeds?

“Kes will be imagined, with the help of lighting,” says Betteridge. “It’s rather like having blood on stage, either you do all blood, and worry about it looking like blood, or no blood at all and let the imagination work overtime.”

Till has included a scene that was not in the film - when Billy takes his dead bird to a disused cinema.

“The last time he was with his dad, his dad took him to that cinema,” says Betteridge. “He starts to ‘tell’ his dad about the bird and how he trained it and in that same moment he lets his dad go and he moves on.”

There is a favourite moment that she asked Till to be sure to include. Mr Farthing, Billy’s English teacher, has been to the Casper home to see the kestrel. Billy does not see Farthing as anything other than a teacher. He offers Billy a lift back to school but Billy says no; he cannot be seen arriving at school with a teacher.

Betteridge sees Jud, the bullying step-brother, as being just as bruised as Billy. She wants to emphasise the contrast between them: Jud is a coal miner and is deep underground; Billy has found a life in the woodland.

“Jud is a bastard and it’s something he can’t stand being called,” she says. “He’s jealous of Billy because Billy has a dad, even though Billy’s dad has run off.”

She has a theory. Barry Hines’s most recent novel Elvis Over England has a central character, married with children, who blows all his redundancy money on a red Cadillac.

There are flashbacks to the school playground and somebody calls him a bastard. He does not understand the word until his mother explains it to him.

“He’s Jud a few years on,” says Betteridge. “It’s the whole bastard thing again.”