Veteran British director Ken Loach has won his second Palme d'Or at the Cannes Film Festival for I, Daniel Blake - a stark and polemical portrayal of a disabled man's struggle with the social welfare system in England.

The left-wing 79-year-old was presented the festival's top prize by actor Mel Gibson at a ceremony on the French Riviera. Accepting the award, the silver-haired Loach punched his fists in the air in victory and said that he hoped his social realist film would give out a message of hope.

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I, Daniel Blake is a warm and realistic drama about a middle-aged widower who, after a heart attack, can neither work nor get government money. It follows his sometimes comic, frequently painful frustrations as he winds his way through an archaic system that seems designed to bring him down.

Loach has long brought his distinct portrayals of the British working class to Cannes. He has had 12 films in competition at the festival over the years, including his Palme d'Or-winning The Wind That Shakes the Barley, which was set not in Britain, but Ireland.

Like many of Loach's films, social politics is at the heart of I, Daniel Blake.

'A conscious cruelty'

"There is a conscious cruelty in the way that we are organising our lives now, where the most vulnerable people are told that their poverty is their own fault," Loach told reporters earlier in the festival. "If you have no work it's your fault you haven't got a job. Never mind in Britain, there is mass unemployment throughout Europe."

Canadian director Xavier Dolan picked up the runner-up Grand Prize, which has been seen by some critics as a vindication for him personally after his film It's Only the End of the World garnered lukewarm reviews and triggered a spat between him and some film critics. The 27-year-old won the jury prize in 2014 for Mommy.

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The Cannes jury's decisions are famously unpredictable, and take place behind doors closed to the press for the duration of the May 11-22 festival.

Despite mixed reviews, director Asghar Farhadi's film The Salesman picked up several awards including best screenplay and best actor for Shahab Hosseini.

Romanian director Cristian Mungiu, who was a favourite to win the Palme d'Or for Graduation, won the best director award, which he shared with French director Olivier Assayas for his paranormal thriller Personal Shopper, starring former Twilight star Kristen Stewart.

Meanwhile Jaclyn Jose became the first Filipino to win the best actress award. Jose won for her performance as a mother who falls prey to corrupt police after being forced to sell drugs to survive in Ma' Rosa.