BRITAIN and Brussels have become embroiled in a diplomatic spat after Gibraltar was described as a “colony of the British Crown”.

The language was used in a European Council document setting out plans for visa-free travel for Britons after Brexit, which noted the "controversy between Spain and the UK" over the sovereignty of the Rock. A footnote stated: “Gibraltar is a colony of the British Crown.”

Fears have been raised that Theresa May’s bid to reopen the Withdrawal Agreement to scrap the Irish backstop could tempt Madrid to renew the row over its claim to Gibraltar.

Downing Street was quick to respond to the “colony” reference with the Prime Minister’s spokesman insisting: "It is completely unacceptable to describe Gibraltar in this way.

"Gibraltar is a full part of the UK family. This will not change due to our exit from the EU," he said.

Fabian Picardo, Gibraltar's Chief Minister, pointed the finger at Madrid, accusing it of trying to "bully" the British Overseas Territory by demanding the contentious description in the draft document.

"No one will be surprised to hear the Spanish Government making provocative statements in respect of Gibraltar. The 32,000 people of Gibraltar are used to the constant attempts by successive Spanish governments to bully us in every possible way.

"This is no different to the sort of abuse we have had from former Spanish administration," he added.

In November, a row with Pedro Sanchez, the Spanish premier, over the Rock almost derailed efforts to agree the Brexit Withdrawal Agreement between the Prime Minister and the EU.

It was only resolved after a clarification about the legal position and emergency talks involving Mr Sanchez, Jean-Claude Juncker, the European Commission President, and Donald Tusk, the European Council President.

Spain ceded Gibraltar to Britain in perpetuity in the 1713 Treaty of Utrecht.

In June 2016 in a referendum on the Rock, 96 per cent of those taking part voted to stay part of the UK; turnout was 84 per cent.

In other developments:

*Dominic Raab, the former Brexit Secretary, questioned whether David Lidington, the PM’s de facto deputy, who backed Remain in the 2016 EU referendum, had the “kind of Brexiteer credentials” to be part of Mrs May’s enhanced Brexit negotiating team.

*John Bercow, the Commons Speaker, insisted in an interview with US TV channel CNN, that he was neutral on Brexit and only wanted to give voice to "minority or dissident" in the Commons. He expressed "concern" that no resolution had been reached on Brexit but stressed: "It isn’t something the Speaker can determine."

*Nick Boles, the former Conservative minister, who was the co-sponsor of the unsuccessful Yvette Cooper’s amendment to extend the Article 50 process, described the forthcoming second meaningful vote on Brexit as the "last chance saloon" to prevent a no-deal outcome.

*DUP leader Arlene Foster urged the EU to “face up to reality" on the backstop, saying: "The blockage to getting a deal is the backstop; therefore, there must be sensible engagement and a pragmatic approach.”

*No 10 brushed off a suggestion from Helen McEntee, Ireland’s Europe Minister, that the UK bid to extend Article 50 would “be approved if requested”. The PM's spokesman insisted: "We have not requested an extension and we will be leaving on March 29."

*Simon Coveney, Ireland’s Deputy PM, is preparing to visit America to talk, among other things, about Brexit, prompting speculation he will seek support from Washington for its position on the backstop. When asked about the prospect, No 10 said the Tanaiste’s travel plans were a "matter for Mr Coveney".

*A new Brexit party backed by Nigel Farage, the former Ukip leader, has received pledges worth more than £1 million and is said to be lining up candidates to fight a snap General Election.