Updated 5.15pm

British Prime Minister Theresa May has accused European politicians and officials of seeking to affect the outcome of the June 8 national election by issuing threats over Brexit.

Speaking in front of her Downing Street office after visiting Queen Elizabeth to mark the dissolution of parliament, the formal start of the election campaign, May said there were some in Brussels who did not want to see Brexit talks succeed.

Over the weekend a German newspaper gave a damning account of talks last week between May and European Commission President Jean-Claude Juncker, reporting that he had told May during a dinner at Downing Street that Brexit could not be a success.

"In the last few days we have seen just how tough these talks are likely to be. Britain's negotiating position in Europe has been misrepresented in the continental press, the European Commission's negotiating stance has hardened, threats against Britain have been issued by European politicians and officials," she said.

"All of these acts have been deliberately timed to affect the result of the general election."

May, whose Conservative Party have a double-digit lead in the polls, said reaching the best Brexit deal would be the overriding task for whoever wins the June 8 election and called on voters to give her their backing to "fight for Britain".

She said that while Britain wanted to reach a deal with the EU, that view was not shared by everyone in Brussels.

"The events of the last few days have shown that, whatever our wishes, and however reasonable the positions of Europe's other leaders - there are some in Brussels who do not want these talks to succeed. Who do not want Britain to prosper."