The director Ken Loach has said he does not want David Cameron to watch his latest film, which deals with unemployment, poverty and the rise of food banks in Britain today, because punishing the poor is part of the prime minister’s project.

Last week, Loach became the first British director to win the Palme d’Or at Cannes twice, when his welfare state polemic I, Daniel Blake picked up the prize.

The 79-year-old film-maker had previously announced he was finished with directing but became so infuriated by the plight of the poor under the current Conservative government that he came out of retirement to make a new film, addressing the human cost of their policies.

But speaking at the premiere of Versus, a documentary about his life and work, Loach said he thought there was no point in “Cameron and co” watching the film “because that is their project, that is what they believe in ... It is part of what they want to happen.”

He said: “It is not an accident that the poor are punished for their unemployment. That’s their project, that’s the point, that’s what has to happen because their model of society produces unemployment and if people question that model then they are lost ... There’s no point in showing the film to them.”

Loach is notoriously outspoken in his condemnation of the Conservative party and their attacks on welfare provision, which have increased poverty across the UK and led to the rise in use of food banks. In the past, he became so critical of the Labour party, which he said was in the grip of “rightwing, Blairite groups” that he co-founded the Left Unity party in 2013 to challenge the capitalist status quo.

At one point, it had about 1,500 members but lost 400 after the election of Jeremy Corbyn as Labour leader.

Loach said Corbyn’s leadership had restored his faith in Labour as a political party that “stands for the interests of ordinary people”.

He admitted he was considering rejoining Labour “because that’s where the battles will be fought, in the constituency parties, in the trade unions, in the community organisation and that’s a very good reason to join the Labour party.”

I, Daniel Blake, winner of this year’s Palme d’Or Photograph: PR

However, Loach said he would remain in Left Unity for the time being, so as not to “pull the rug out” from those who still wanted the party to continue.

The documentary included the revelation that, at the age of 11, Loach stood as the Conservative party candidate in his school elections. “I was only a lad at the time so I wouldn’t read into it too much” he said with a laugh.

Drawing on his own use of platforms such as the BBC and Channel 4 to broadcast some of his most politically subversive works, such as Cathy Come Home in 1966, which addressed poverty and homelessness, Loach appealed to film-makers to “stay within the big institutions and fight within”.

He said the BBC today had an “authoritarian, censoring, controlling presence” that needed to be challenged. “I think it is really difficult [to make subversive films] because of the culture of micromanagement in the big television companies,” he said.

“I know with new technology, people are able to independently make films very simply but I hope they don’t give up battling within the big organisations because they are ours. The BBC is ours, goddammit.”

Despite being the only Briton to have two Palme d’Or’s to his name - the first was for The Wind That Shakes the Barley in 2006 – Loach downplayed his success at the Cannes festival with I, Daniel Blake. “There was a generous audience and a friendly jury,” he said with a laugh. “It was a bit like playing at home with a good ref.”