[BERLIN] The European Union should aim to keep as close a relationship with Britain as possible after Brexit, German Economy Minister Sigmar Gabriel said on Thursday.

Germany, the EU's largest economy, is concerned about the likely financial costs of Brexit but has also stressed the need for a unified stance among member states in the divorce talks, warning Britain against trying to "cherry-pick" the bits of EU membership it would like to preserve.

"My personal point of view is: We should do everything, as far as this is politically justifiable, to keep the Britons as close as possible to Europe," Mr Gabriel told foreign reporters, without elaborating.

Mr Gabriel, who is also head of the Social Democrats (SPD), the junior partner of Chancellor Angela Merkel's conservatives in Germany's ruling coalition, said the Brexit negotiations must not be allowed to drag on too long.

"This won't be easy. But above all, we must get this done quickly. The uncertainty is the biggest problem," Mr Gabriel said.

British Prime Minister Theresa May has said she will invoke Article 50 of the EU's Lisbon Treaty that triggers the exit negotiations by the end of March 2017.

Ms Merkel repeated on Tuesday her view that access to the EU's single market of nearly 500 million people hinged on respect for the bloc's four basic freedoms - of movement of people, goods, services and financial market products.

Controlling immigration was a major issue for many of the 52 per cent of Britons who backed leaving the EU in the June referendum.

REUTERS