It is a “myth” and "bollocks" that the free movement of people is one of the European Union’s founding principles, according to Foreign Secretary Boris Johnson.

In a colourful interview with the Czech daily Hospodářské noviny Mr Johnson also appeared to go further than any of his Cabinet colleagues and dismiss Britain being part of the customs union after Brexit.

“Probably, we will need to leave the customs union, but this is a question which will be dealt with in the negotiations," Mr Johnson told the newspaper.

The Hospodářské noviny also quoted Mr Johnson as using the word "bollocks" in reference to the idea of the free movement of people being a founding principle of the EU.

To many EU officials the union’s four freedoms – goods, services, capital and the free movement of people – are essential to membership. But in the interview, Mr Johnson, added: "It's a total myth - nonsense. It is stupid to say that freedom of movement is a fundamental right. It's something that has been acquired by a series of decisions by the courts.

"And everyone now has in his head that every human being has a fundamental, God-given right to go and move wherever he wants. But it is not.

"It was never a founding principle of the European Union. It's a complete myth. Total myth."

When asked about Donald Trump, the President-elect of the United States, Mr Johnson added that there was every reason to be "positive". He said: " Donald Trump is dealmaker, he is a guy who believes firmly in values that I believe in too — freedom and democracy. As far as I understand he is in many aspects a liberal guy from New York."