The UK must make clear that it intends fundamentally “to rethink its Brexit strategy” if it wants to get a lengthy extension to the negotiation process, European Council president Donald Tusk has said.

EU leaders, though fearful of a no-deal departure, are certain to set conditions which may be difficult for the UK to meet.

While encouraging the 27 remaining member states to “be open to a long extension” for the UK, Mr Tusk said in a Twitter post on Thursday that such a request would only get the unanimous support it will need if the UK revisits its red lines in the negotiations.

The UK has been told it will be required to make a “credible justification” for any extension it seeks, and prime minister Theresa May will need to present such a case to the EU summit next Thursday.

During my consultations ahead of #EUCO, I will appeal to the EU27 to be open to a long extension if the UK finds it necessary to rethink its #Brexit strategy and build consensus around it. — Donald Tusk (@eucopresident) March 14, 2019

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Some officials in Brussels wonder if the EU leaders will feel they can make a decision at such short notice.

Viable scenarios for extension

Brussels has been making clear for days that it believes there is no more room for negotiation on the withdrawal agreement, twice rejected by the House of Commons, and that any British strategy based on that approach would be pointless.

The European Commission was unwilling to comment or elaborate on Mr Tusk’s Twitter post.

However, a commission spokesman envisaged three potentially viable scenarios for an extension request: a request for a short – say three-month – “technical” extension in the event Mrs May wins approval of the withdrawal agreement at the third attempt next Wednesday; a request for a short extension to complete no-deal planning in the event the government acknowledges it can go no further and plans to leave without a deal; and a request for a long extension – say a year – based on a radically new approach.

Irish officials kept their cards close to their chests on which option Dublin might favour except to insist that the UK will have to make a strong “reasoned case”.