DAVID CAMERON cynically offered a “guarantee” of workers’ rights yesterday if Britain stays in the European Union — just weeks after hitting trade unions with fresh restrictions.

The Tory Prime Minister twice used a speech during a cross-party Remain campaign event to claim employment rights were in danger from a break with Brussels.

Lining up alongside Labour’s former acting leader Harriet Harman, Liberal Democrat leader Tim Farron and Green Party leader Natalie Bennett, he said: “We come together today in an unprecedented show of cross-party unity.

“We offer a guarantee: if we vote to stay in a reformed Europe, we will continue to have full access to the free-trade single market, the largest in the world, with all the jobs, low prices, investment and opportunities for young people that brings.

“Workers’ rights will be protected and we can better deal with global problems like terrorism and climate change.”

The four politicians came together to unveil a dossier which they said exposed the Leave campaign’s “con tricks” on trade, spending, workers’ rights and environmental protections.

Mr Cameron added: “This dossier outlines all the various and often contradictory positions they’ve held on the economy — from trade to public spending, workers’ rights to environmental protections.

“And it is, in my mind, the most damning indictment of the Leave campaign.”

But his warnings over the future of workers’ rights came just a month after the government forced into law the hated Trade Union Act, which breaches International Labour Organisation regulations.

And the Morning Star has reported how an attempt to weaken employment rights was initially part of Mr Cameron’s EU renegotiation stance.

Asked about the negotiations by Ukip MP Douglas Carswell last year, he replied: “Making sure we deal with the issue of competitiveness, which, yes, does impinge on some of the issues, under what was called the social chapter, that have never been acceptable to the United Kingdom.”

Bakers’ union general secretary Ronnie Draper said Mr Cameron’s claims would have no credibility with trade union members.

He told the Star: “Is this the same PM from the same party that just passed the Trade Union Act?

“I think that is so rich coming from someone who introduced the Trade Union Bill. I think that is absolutely cynical.

“Will people believe him? No chance.

“In or out of Europe, we are going to get screwed anyway [with] a Tory government.”