Brexit summit gets green light after 11th-hour diplomatic haggling sees Spain brought on board

EU leaders will meet tomorrow to endorse the Brexit deal after 11-hour diplomatic haggling to bring Spain on board.

Spanish prime minister Pedro Sanchez had been threatening to scupper the summit over concerns on Gibraltar but he has agreed to attend after securing written assurances from UK diplomats and speaking to senior European figures.

On the eve of the summit the UK ambassador to the EU, Sir Tim Barrow, wrote to reassure Madrid that Gibraltar would not necessarily be covered by future trade arrangements after Brexit, leading Mr Sanchez to claim that Britain would be forced to open talks on “joint sovereignty” with Spain.

Arriving for the summit in Brussels, Ms May said Gibraltar was “covered by the whole withdrawal agreement”, and that she would always “stand by’’ its citizens.

European Council president Donald Tusk announced the summit would go ahead on Twitter, saying: “I will recommend that we approve on Sunday the outcome of the Brexit negotiations.

“No one has reasons to be happy. But at least at this critical time, the EU27 has passed the test of unity and solidarity.”

Negotiators were at work throughout the night to broker a deal to reassure Spain over Gibraltar without reopening the withdrawal text, which both London and Brussels consider to be agreed.

Mr Sanchez confirmed that a deal had been reached, allowing invitations to be sent to the remaining EU leaders for the special summit, where Theresa May is hoping to get her Brexit blueprint approved.

The row centres on Spain’s claims that the future relationship to be negotiated between the EU and UK should not apply to Gibraltar and that it should only be decided between itself and Britain.

But Ms May said the plan must apply to “the whole United Kingdom family”, which appears to include Gibraltar, which has been a British overseas territory since the 18th century.

British diplomats have broken the impasse by confirming the government’s position that a future trade deal will not automatically cover Gibraltar.

A UK government spokesman said: “For the withdrawal negotiations, given there are some circumstances which are specific to Gibraltar, we held talks with Spain which directly involved the government of Gibraltar.

“These were constructive and we look forward to taking the same approach to the future relationship.”

Mr Sanchez said “this is going to allow us to have direct negotiations with the UK regarding Gibraltar”. He added: “Once the UK has left the EU, Gibraltar’s political, legal and even geographic relationship with the EU will go through Spain.”

The prime minister was due to head to Brussels on Saturday for last-minute talks on selling her deal with Mr Tusk and European Commission president Jean-Claude Juncker.

However, she still faces major opposition at home, with both Boris Johnson and her DUP allies urging her to “bin” the deal.

Fabian Picardo, Gibraltar’s chief minister, later said that Ms May’s government had been “completely firm in its resolve and in our support”, and that “the sovereignty of Gibraltar is and will remain entirely British”.