Donald Tusk has set out the EU’s draft negotiating position, making clear that Britain must start to deal with its divorce from Europe before talks on future trade terms.

The European Council President’s nine-page document states that there must be “sufficient progress” on withdrawal talks – including a “divorce bill” potentially running as high as £50bn – before negotiations on future relations begin.

The guidelines also make clear that the EU is willing to consider a “transitional” deal after Brexit and is also ready for talks to fail.

It comes after Theresa May triggered Article 50 on Wednesday with a letter calling for withdrawal and trade talks to start at the same time, while sparking anger by linking security cooperation to future trade bargaining.

Mr Tusk’s document said: “In these negotiations the Union will act as one. It will be constructive throughout and will strive to find an agreement. This is in the best interest of both sides.

“The Union will work hard to achieve that outcome, but it will prepare itself to be able to handle the situation also if the negotiations were to fail."

The draft sets out a staged approach to talks, with the first part dealing with disentangling existing relations between London and Brussels. This will be the moment that both sides will settle how much the UK’s “obligations” are, in terms of a divorce bill.

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The move flies in the face of Ms May’s call for talks on withdrawal and future trade terms to start at the same time, but does leave open the possibility of them eventually taking place in tandem as long as divorce talks advance.

The second part of the EU’s process will begin to set a framework for negotiations on a potential trade deal, while the third part will deal with the transition from the old to the new relationship.

The paper, which sets the scene for two years of tough Brexit talks, has now been sent to European capitals before a full negotiating mandate is cemented at a summit on 29 April.

The guidelines will form the basis of a mandate for chief EU negotiator Michel Barnier, who expects to launch negotiations in early June.

It means he will have some 16 months to conclude the basics of a withdrawal treaty and future relations framework that can then be ratified by lawmakers on both sides in time for Brexit on 29 March 2019.

The guidelines put no timeframe on how long a potential transition between Brexit and a new relationship should last, though many EU officials believe it could be between two and five years.

A UK Government spokesman said: “These are draft guidelines and we look forward to beginning negotiations once they have been formally agreed by the 27 member states.