Former Twickenham MP Vince Cable has stunned his traditional left-wing supporters by calling an end to free migration of EU citizens into Britain after Brexit a “political necessity”.

The Liberal Democrat, who lost his seat to Tania Mathias in 2015, said despite his liberal instincts and he has "serious doubts" that EU free movement is "tenable or even desirable".

The staunch Remain supporter said the debate over immigration is now largely "colour-blind" and that free movement in fact discriminates against the likes of Indians, West Indians, Americans and Australians, who face tough visa controls.

Sir Vince as called for a more "rational immigration policy", including guaranteeing the rights of EU nationals already in the UK, and the removal of students from net migration figures.

Writing in the New Statesman, he said: "I have serious doubts that EU free movement is tenable or even desirable.

"First, the freedom is not a universal right, but selective. It does not apply to Indians, Jamaicans, Americans or Australians. They face complex and often harsh visa restrictions.

"One uncomfortable feature of the referendum was the large Brexit vote among British Asians, many of whom resented the contrast between the restrictions they face and the welcome mat laid out for Poles and Romanians.

"There is no great argument of liberal principle for free EU movement; the economics is debatable; and the politics is conclusively hostile.

"Those benefits are real, which is why the Government must prioritise single market access and shared regulation. Yet that may not be possible to reconcile with restrictions on movement."

Sir Vince served Twickenham as MP for 18 years and business secretary under the previous coalition government.

The Lib Dems have distanced themselves from the politician. A party spokesman said yesterday: “Vince’s views are his own, he is not a member of parliament and he does not speak for the party.”