The affecting sight of a kestrel carving through the air having been so memorable a part of Ken Loach’s award-winning film Kes, theatregoers are bound to feel slight disappointment at a stage version of the story – from Barry Hines’s 1968 novel A Kestrel for a Knave – which at no time shows us a live bird, even on a glove, still less in flight. Presumably, Elf and Safety are in part to blame.

Hamlet without the prince, then? Only partly, I think. Lawrence Till, the writer of the new adaptation, argues in a programme note that “the play isn’t really about the kestrel at all”. This is taking things a little far (‘at all’!), but it is certainly true that the bird is important only for its transforming effect – alas only a temporary one, surely – on the 15-year-old Barnsley boy who finds and trains it.

The truly magical moment, on stage as in the film, comes when the usually uncommunicative Billy Casper (the excellent Stefan Butler) – encouraged by a sympathetic schoolmaster (Dominic Gately) to describe his hobby to the rest of the class – speaks with lyrical enthusiasm of Kes. This vividly brings the bird to life, as does Guy Hoare’s lighting which at times presents the audience with a compelling shadow image, suggestive of a crucifix, of wings spread in flight.

As an unsentimental study of a boy raised to be one of life’s losers – abandoned at six by his dad and saddled with a slut of a mum (Katherine Dow Blyton) and a drunken bully of a brother (Oliver Farnworth) – Kes can hardly be other than sad.

Through the spot-on-accurate fashions and music (Animals, Simon and Garfunkel) director Nikolai Foster fixes the action firmly in 1969. This raises the question of whether we are being shown a sorry world entirely different from that of 2009.

I would like to think that we are, certainly in terms of the scenes of school life that play a major role in the drama – well done Oxford School for supplying many of the pupils. While the bully-boy tactics of the odious sports master (David Crellin) can still perhaps be seen, the outrageous assaults – the cane on bare hands – practised by the smug and sadistic headmaster (Mike Burnside) now appear all too obviously to be a horror from another age.

With mining in Barnsley extinct, there would now be no excuse – if excuse it be – for the appalling actions of brother Jud, who regards a skinful on a Saturday night, and what might follow from that, as his natural reward for a week of back-breaking work. But no doubt he would now be in some other dead-end job or else unemployed, along, I fear, with Billy.

Perhaps unconsciously inspired by another northern Billy (Elliot), Nikolai Foster has introduced balletic movement into the play, mostly supplied by Billy himself and by his schoolboy persecutor MacDowell (Oliver Watton). I found this a bit of a puzzle. Others, perhaps, might be occasionally puzzled by the impenetrability of the heavily accented speech – the reason for a 12-month delay in the release of the film. But as one living at the time within a few miles of Barnsley, I had no such problem, then or this week.

Until Saturday. Tel: 01865 305305 (www.oxfordplayhouse.com).