UK may have to leave EU customs union but can maintain free trade - Boris Johnson

Britain may have to leave the European Union's customs union when it officially leaves the bloc, but it can maintain free trade, British foreign secretary Boris Johnson was quoted as saying on Tuesday.

Johnson said in a newspaper interview that he believed Britain could have control over immigration while also keeping the benefits of access to the single market such as "passporting" rights for banks in Britain to do business in Europe.

"We want to leave the EU legal framework and treaties. We will probably have to leave the customs union, but that is a question that will be discussed," Johnson told Czech daily Hospodarske Noviny, in remarks published in Czech.

"I believe it can be done and at the same time maintain free trade and growing European economies."

He reportedly said "no" when asked whether he could imagine losing access to the single market.

A leaked cabinet paper revealed by the Guardian last month showed that ministers have been warned that pulling out of the EU customs union could lead to a 4.5% fall in GDP by 2030 and the clogging up of trade through Britain’s ports.

The issue has caused a split among ministers, with Liam Fox, the trade secretary, pushing for the UK to leave because membership of the customs union prevents the negotiation of independent trade deals with non-EU countries.

On the other side, Philip Hammond, the chancellor, and his allies have concerns about the impact of leaving on the economy.

Pressed repeatedly on whether Johnson was right to say the UK would probably leave the customs union, a spokeswoman for Prime Minister Theresa May said that Johnson’s comments reflected the government's position, which is that “a decision hasn’t been taken."

Johnson told the Czech paper that the free movement of people - which along with the movement of goods, capital and services, is one of the EU's "four freedoms" - was not a "founding principle" of the bloc, implying that it was not as fundamental as the single market.

"Everybody now has in their heads that every human being has some basic, God-given right to go and move wherever he wants. But it is not so. It never was a founding principle of the European Union. It is an utter myth."

German Chancellor Angela Merkel said on Tuesday that the EU could not separate the four freedoms in order to allow Britain to restrict immigration from the bloc, while retaining tariff-free access to the market of close to 500 million people.