Boris Johnson insisted the UK and the EU would forge a relationship as “friends and sovereign equals” after Brexit as he signed the document agreeing the terms of Britain’s departure.

The Prime Minister and the Presidents of the European Council and the European Commission all signed the Withdrawal Agreement in what Mr Johnson described as “a fantastic moment”.

He added: "This signature heralds a new chapter in our nation's history."

But in a sign of the battles still to be fought, The Telegraph has learnt that France has insisted in closed-door European Commission meetings that Britain must grant EU countries access to UK fishing waters for 25 years after Brexit if it wants a free trade agreement with Brussels.

The EU has warned that successfully concluding a fishing deal with the UK - ideally by July 1 this year - is a prerequisite for any future trade deal, which Mr Johnson wants done by the end of this year.

Britain is understood to be willing to accept only a one-year agreement on quotas and fishing rights, setting up the first big showdown of negotiations that will start in March.

On a day of huge ceremonial significance, Ursula von der Leyen, the European Commission President, and Charles Michel, the European Council President, signed the Withdrawal Agreement document in the same room in Brussels in which Britain’s permanent representative to the EU handed over Theresa May’s letter triggering Article 50 almost three years ago.