THERESA May has called for a "mature and co-operative" relationship between Britain and the EU as she seeks a "smooth" Brexit, which she said could be in the interests of both sides.

The Prime Minister was speaking at the conclusion of her first European Council summit, at which she was given just five minutes at the end of dinner in the early hours of Friday morning to set out her position on Brexit.

Her demands for Britain to play a full role in the European Union while it quits the bloc sparked anger in Brussels with some senior figures saying it was wrong for the UK to try to shape the future of the EU while it was trying to leave.

In a press conference at the end of the two-day summit, Mrs May said: "I recognise the scale of the challenge ahead. I'm sure there will be difficult moments. It will require some give and take.

"But I firmly believe that if we approach this in a constructive spirit - as I am - then we can deliver a smooth departure and build a powerful new relationship that works both for the UK and for the countries of the EU looking for opportunities, not problems.”

While Mrs May said she wanted to see the completion of the EU trade deal with Canada, it seemed to be on the verge of collapse after the Canadian trade minister walked out.

Chrysta Freeland said talks with the Walloons and EU representatives had failed to make progress and she questioned the bloc's ability to strike any international agreements. “It's impossible,” she declared, adding: “We've decided to return home. I'm really, really sad. Truly."

Meantime, the PM slapped down suggestions that the UK-EU Brexit negotiations would be carried out in French after Michel Barnier, Brussels chief negotiator, supposedly said he wanted the divorce talks to be held in his mother tongue.