If immigration to Britain continues at the present rate, the country will need to build the equivalent of three cities the size of Birmingham in the next five years to cope, MPs have been told.

Addressing the Commons Home Affairs Select Committee yesterday, Lord Green of Deddington, chairman of Migration Watch UK, said that immigration plus natural population growth would add around 3 million people to the population by 2020.

Lord Green also expressed doubt that Prime Minister David Cameron can keep his promise of reducing net migration to the tens of thousands while immigration from the EU remains so high.

He told MPs: “It will not be possible to bring overall net migration down unless some action is taken to reduce the flow from European countries to a level that people in this country will accept.”

The Prime Minister first made the pledge upon taking office in 2010, but it soon proved impossible to keep, with net migration actually rising to record levels. Despite the failure, the Prime Minister has restated his promise, although has yet to go into detail as to how he will achieve it.

Lord Green said the government should not abandon the target of getting net migration below 100,000 as it would prove a useful would provide a useful focus for civil servants.

He added that no one expected EU migration to be so high as it was assumed many migrants from Eastern Europe would return home after a few years. “We have a million, which is fine in many respects, but there is no suggestion they are going home.”

Breitbart London reported earlier this week that Lynton Crosby, the man who masterminded the Conservative Party’s surprise victory in this year’s election, privately warned the Cabinet they risk losing the next election unless they cut immigration.

According the book Why The Tories Won – The Inside Story Of The 2015 Election by journalist Tim Ross, Crosby produced private polling that showed immigration was the biggest fear for voters who backed the Conservatives in May.

Mr Cameron admitted in January that he had failed to control immigration, telling BBC Radio Two: “That is what I wanted to achieve. But the figures are very clear I have not achieved that, I want to keep going until we do achieve it because I believe it is the right thing for our country.”