By Ana Nicolaci da Costa and John Geddie
LONDON (Reuters) - German Finance Minister Wolfgang Schaeuble said on Thursday it would be extremely difficult or even impossible for Britain to negotiate a "special deal" on trade with the European Union if it voted to leave the 28-member bloc.
Britain will hold a referendum on June 23 on whether the country wants to remain part of the EU, after clinching a deal Prime Minister David Cameron hopes will convince Britons to vote in favour of membership.
Schaeuble urged Britain to stay in the EU, warning that Europe could become less stable if it leaves and that the bloc could also become less competitive.
Speaking about the possible options touted by British press for trade deals after a so-called Brexit, Schaeuble said during an event in London:
"It would be extremely hard or even impossible to negotiate a special deal in a post-Brexit atmosphere."
Supporters of Britain leaving say the country would be able to strike its own free trade deals and its existing EU partners would not want to hurt bilateral trade.
But critics say Britain would struggle to negotiate favourable terms having just renounced membership to the world's largest trading bloc, and a majority of economists in a Reuters poll last month said its trade balance would worsen following an exit.
Schaeuble said the decision was for the British people but that Britain's departure would weaken the European Union, as well as the global economy in the medium-term, and would be a long, cumbersome process.
"Imagine the negotiations that would have to take place after a Brexit decision. For the years to come all this bureaucratic stuff. Good luck!," he said at a separate event in London.
"Imagine all the trade agreements the European Union has with about 60 other nation states. The UK would have to negotiate all these agreements again. Good luck!"