Workers from Bulgaria and Romania will not be allowed free access to Britain's labour market when their countries join the European Union, the government will announce tomorrow.
John Reid, the Home Secretary, is expected tell MPs that the government has concluded that the new entrants cannot be allowed the same freedoms that were extended to ten other new EU countries in 2004.
Romania and Bulgaria join the union in January, and ministers have been convinced that allowing their nationals unrestricted freedom to work in Britain would be politically unacceptable.
Since May 2004, more than 600,000 eastern Europeans have come to work in Britain. While both the Treasury and the Bank of England say such migration boosts the UK economy, some Labour MPs fear the new entrants push down wages for the party's traditional voters.
Mr Reid is expected to argue that Romania and Bulgaria have too many unskilled workers to allow free entry. Instead, rules would be set out to control entry, favouring those with particular skills and trades.