DAVID CAMERON sparked fresh fear yesterday that watered-down workers’ rights will be part of his price to keep Britain in the European Union.

The Prime Minister revealed that “competitiveness” is one of four red lines in the renegotiation of Britain’s membership.

In a letter to European Council president Donald Tusk, he called for a “target to cut the total burden on business.”

The Star revealed this week how the CBI bosses’ lobbying group has criticised laws limiting working hours more than any other EU policy.

And CBI president Paul Drechsler gave an enthusiastic welcome yesterday for Mr Cameron’s “vision for a more competitive EU that works for business.”

TUC general secretary Frances O’Grady said voters would be more likely to support leaving if the renegotiation “turns out to be a way to roll back rights.

“David Cameron must spell out his position on workers’ rights,” she said.

“The real way to win public support for the benefits our EU membership brings is to campaign for better employment rights — not worse treatment at work.”

The Prime Minister’s plan to stop in-work benefits and access to social housing until migrants have lived in Britain for four years also faced opposition.

The European Trade Union Congress said it was calling on other EU states to reject changes that will “undermine freedom of movement of workers, and equal pay for equal work.”

General secretary Luca Visentini said: “Trade unions cannot accept discrimination against workers from other member states. Not in the UK, not anywhere in the EU.”

A European Commission spokeswoman said the suggestion would be “highly problematic” for other EU member states.

And Mr Cameron has already hinted he may be willing to drop the policy, saying: “I understand how difficult some of these welfare issues are.”

The Prime Minister has promised to leap “headlong” into the campaign to keep Britain in the EU if he secures his reforms.

But his speech caused tension within the Britain Stronger in Europe Campaign.

Green MP Caroline Lucas, who sits on the board of the In campaign, said: “Cameron’s vision for an EU based on little more than an increasingly deregulated free market is deeply depressing.”