I, Daniel Blake review: Ken Loach at his most moving - and most vital

"My name's John Ford. I make Westerns." Thus one of the great directors (slightly disingenuously) summed up his career. Here is the latest film from Ken Loach. There is great variety to his work – recently swerving towards nostalgia with Jimmy's Hall and Ealingesque comedy with The Angel's Share – but, just as Ford will always be associated with the western, Loach will forever by tied to this class of rooted, moving, well-researched social realism.

Indeed, no film in his long career has carried so many echoes of his 1966 TV drama Cathy, Come Home. There is the same rage against a system rigged to frustrate the disadvantaged. There is the same compassion for those crushed by the machinery. He and writer Paul Laverty, collaborators for 20 years, earned the Palme d'Or the film won at Cannes in May.

In I, Daniel Blake, the robust, soft-featured Dave Jones, best known as stand-up comic, plays a Tyneside carpenter who, following a heart attack, is told to lay off work for a while. Following an unhappy encounter with a "health professional", he is denied disability payments.

He then encounters absurd logistical conundrums when applying for “jobseeker’s allowance”. In order to qualify, he must seek work that, if offered, he will be unable to accept. Early on in the process, Daniel meets Katie (Hayley Squires), a young London woman dispatched to Newcastle with her two children by a welfare service that claims no affordable housing exists in the capital.

In the early stages, Loach and Laverty extract much black humour from the sheer lunacy of the regulations. Evasive euphemisms abound. Almost no official can find the language to communicate with an applicant who, like Daniel, has never turned on a computer. In a paradox worthy of Kafka, solutions to IT illiteracy seem to be found almost exclusively online. Meanwhile, Katie, despite Daniel’s help, drifts deeper into debt and takes to shoplifting.

I, Daniel Blake looks to have been rigorously researched. The bureaucratic circumlocutions call themselves by names that sound all too real. Katie's eventual trip to a food bank plays as if transcribed from first-hand reports. Sometimes this pushes the film into the territory of fictionalised case study. Now and then, Loach wields a sledgehammer when a more delicate tool would have sufficed.

These are mere quibbles. The emotional truth cannot be argued with. When this film-making partnership chooses to exercise its anger, the results are always skull-shaking, but there are at least two scenes in I, Daniel Blake that are as moving as anything in Loach and Laverty's many collaborations.

Johns gives us a man who, a striver all his life, finally meets a match for his determination in a system that seems cynically structured to frustrate honest aspirations. Johns’ task is not an easy one. The joiner’s generosity and courage are so mighty that the character could easily have come across as implausibly saintly, but the actor seasons with just enough salt to make Daniel believable. Squires gets across the sheer exhaustion that poverty imposes on even the young and energetic.

Robbie Ryan, the great Irish cinematographer, photographs the Newcastle streets with a simple clarity that contrasts interestingly with his more poetic work on Andrea Arnold's current American Honey. The supporting players have the ease of delivery we expect from Loach productions. George Fenton's music is effective, but unobtrusive.

It would be easy to underestimate the quiet brilliance of this moving film. Like Cathy, Come Home, it constitutes a detailed record of the precise techniques by which the disenfranchised are further degraded. But the passionate contributions from all concerned inject an emotional punch that few mere "docudramas" could manage.

His name is Ken Loach. He makes Ken Loach films. And this is his best in a generation.