[3] Kes follows the story of Billy, who comes from a dysfunctional working-class family and is a no-hoper at school, but discovers his own private means of fulfilment when he adopts a fledgling kestrel and proceeds to train it in the art of falconry.

The film has been much praised, especially for the performance of the teenage David Bradley, who had never acted before, in the lead role, and for Loach's compassionate treatment of his working-class subject; it remains a biting indictment of the British educational system of the time as well as of the limited career options then available to lower-class, unskilled workers in regional Britain.

Fifteen-year-old Billy Casper, growing up in the late 1960s in a poor South Yorkshire community dominated by the local coal mining industry, has little hope in life.

Billy's father left the family some time ago, and his mother refers to him at one point, while somberly speaking to her friends about her children and their chances in life, as a "hopeless case".

For the first time in the film, Billy receives praise, from his English teacher after delivering an impromptu talk about training Kes.

His younger brother Richard had found a new life after his student experiences at the local secondary modern school by training the original bird "Kes", the inspiration for the movie.

Kes protests at this educational void that does not take into account individual skills, and suggests this is a consequence of capitalist society, which demands a steady supply of unskilled labour.

[2][16] In his four-star review, Roger Ebert said that the film failed to open in Chicago, and attributed the problems to the Yorkshire accents.

[17] Ebert saw the film at a 1972 showing organised by the Biological Honor Society at the Loyola University Chicago, which led him to ask, "were they interested in the movie, or the kestrel?"

The website's critical consensus reads, "A harrowing coming of age tale told simply and truly, Kes is a spare and richly humane tribute to the small pockets of beauty to be found in an oppressive world.

"[19] In an essay included with the 2016 Blu-ray release of the film, commentator Philip Kent writes: Funny, sad, and bitingly authentic, Kes resonates with Loach's anger at the way so many kids grow up into narrow, option-free lives.

Kes, as Loach has commented, sets up a contrast between "the bird that flies free and the boy who is trapped", but at the same time there's an unmistakable identification between them.

It is often compared with François Truffaut's Les 400 coups (1959), another memorable depiction of adolescent rebellion in an unsympathetic adult world.

Both films are what the French term a cri de coeur, a heartfelt appeal for adults not to write off the next generation and condemn them to a future without meaning, but rather to take the time and the effort to instil in youngsters a sense of self-worth and desire to make something of their lives.

[22]Graeme Ross, writing in 2019 in The Independent, placed the film 8th in his "best British movies of all time", saying: A beautifully filmed adaption of the Barry Hines novel A Kestrel For a Knave with a remarkable performance from David Bradley as Billy Casper, a 15-year-old boy from a deprived background whose life is transformed when he finds a young falcon and trains it, in the process forming a close emotional bond with the bird.

There's comedy and tragedy in equal measure in Kes, with the hilarious football scene with Brian Glover as both referee and Bobby Charlton and the heartbreaking ending demonstrating Loach's devastating gift for both.

The cast of the mostly non-professional actors wasn't told what to expect in many of the scenes, hence the real shock and pain on the boys' faces when they were caned by the bullying headmaster.

With Chris Menges' superb camerawork lit only by natural light, Kes remains a true British classic and the peak of Loach's illustrious body of work.