Employers would be deterred from taking on migrants at the expense of British workers if Labour wins power, opposition leader Ed Miliband said today.

In a major policy switch for his party, Miliband admitted in a speech to the IPPR think tank that the previous Labour government “got it wrong” on immigration, especially in allowing uncontrolled migration from the eastern European countries which joined the EU in 2004.

He said a future Labour administration would impose strict controls should there be any further expansion of the EU, and also unveiled a new set of policies aimed at deterring employers from relying on foreign workers.

These would include a requirement for employers for whom foreigners make up a quarter of their workforce to publish this fact, so that any skills gaps in the British talent pool can be addressed. Recruitment agencies would also be banned from exclusively taking on overseas workers, while the Gangmasters Licensing Authority would have its remit expanded to cover more sectors.

"It was a mistake not to impose transitional controls on accession from eastern European countries,” said Miliband. “We severely underestimated the number of people who would come here. We were dazzled by globalisation and too sanguine about its price.

"By focusing exclusively on immigration's impact on growth, we lost sight of who was benefiting from that growth - whose living standards were being squeezed. We became disconnected from the concerns of working people."

He added that he would not make “promises that could not be kept” on overall immigration numbers, since migration from the existing EU states cannot be restricted by European law. But British workers should be trained in order to level the playing field in sectors currently dominated by migrants, he said.

"The problem we need to address is in those areas and sectors where local talent is locked out of opportunity," he concluded.

But in response, Immigration Minister Damian Green said Labour had no credibility on the issue. "They still don't think immigration was too high when they were in power and they still won't say that immigration needs to come down,” said Green. "That's why they've opposed every one of the government's policies to cut immigration, and it's why they cannot be trusted to run Britain's immigration policy."