Germany's vice chancellor said Britons living in the European Union should be given dual citizenship so they can stay when their country leaves the bloc.

Sigmar Gabriel said on Saturday at a meeting of his centre-left Social Democratic Party in Berlin that Britain's referendum decision to quit the EU was a further reason to campaign to relax the rules on dual citizenship in Germany.

He said: "let us offer it to young Britons who live in Germany, Italy or France, so they can remain European Union citizens in this country".

German law normally requires that anyone applying for citizenship has to relinquish their old citizenship.

Mr Gabriel, who is also the economy minister, told party members that "Europe is the best place in the world for freedom, democracy and the chance of social progress".

Meanwhile, about 50 people protested in front of Berlin's Brandenburg Gate against the British referendum to leave the European Union.

Participants chiefly from Britain held EU flags and home-made placards Saturday bearing such slogans as We Love EU, We're Not Leaving and Brown Sauce.

One demonstrator, artist Daniel Belasco Rogers, said he fears that a British exit could make him a migrant in Germany after 15 years' residency.

Mr Belasco Rogers says he and his family might apply for German citizenship "but I'm hoping they find a loophole and this whole thing doesn't happen".