David Davis, the shadow home secretary, says he would set an annual limit on the number of economic migrants to the UK.

More than 200,000 people have moved to Britain every year since the EU expanded in 2004, with an estimated 77,000 a year finding work in the construction industry.

The Conservatives have promised to set a cap on how many are able to enter if they are elected to government.

Davis said: “Unchecked immigration is not inevitable. It’s what happens when you have a failed policy.”

Davis also announced that, if elected, the Conservatives would use £162m put aside for ID cards to fund the construction of new prisons.