Cabinet sources said the Prime Minister is refusing to publish the attorney general’s advice because it reveals the true consequences her agreement could have on Britain. Upon the publication of the letter in October, the Government was so worried about the truth coming out it numbered the copies of it and forbade ministers from taking the document with them, sources claimed. A minister told The Sunday Times: “The letter was not allowed to leave the room”.
And a cabinet source added: “The legal advice is very bad, which is why they don’t want anyone to see it.”
George Cox, the UK’s attorney general, said in his letter the UK has only one way to escape the customs union under the current deal – strike a trade deal the EU27 will deem good enough for them.
But as this could take years, or not happen at all, and it would risk Britain ending up with a Brexit in name only, trapped forever as a rule-taker satellite of the EU.
Leaked details of the letter published by the newspaper said: “The protocol would endure indefinitely.”
These details have been confirmed by three serving Cabinet ministers and former Brexit Secretary Dominic Raab, and are set to plunge Mrs May into a deeper crisis while she is trying to push her deal ahead of the vote in Parliament on December 11.
Mr Raab, who resigned as Brexit Secretary in protest to Mrs May’s deal last month, confirmed the position of Mr Cox.
He said: “The legal position is clear. The backstop will last indefinitely, until it is superseded by the treaty setting out our future relationship, unless the EU allows us to exit.
“The EU has a clear veto, even if the future negotiations stretch on for many years, or even if they break down and there is no realistic likelihood of us reaching agreement.
“That’s my view as a former international lawyer, but it is consistent if not identical with all formal advice I received.”
Mr Cox will give a statement in the Commons on Monday outlining the legal position of the Government on the Brexit deal, approved last Sunday by the EU27.
And Downing Street is expected to publish a summary of the advice.
However, ministers who read the legal advice said Mr Cox’s statement is far bleaker than No10’s document.
This shocking revelation comes as the Labour Party is poised to work with other opposition parties to start proceedings for contempt of Parliament, in a bid to force the Government to publish Mr Cox’s letter in full.
Labour Shadow Brexit Secretary Keir Starmer said the Government would be “getting into very, very deep water” if it stubbornly continued to keep the public in the darkness over the consequences Mrs May’s deal will have on the UK.
He said: “If they don’t produce it tomorrow then we will start contempt proceedings, and this will be a collision course between the Government and parliament.
”I accept that it’s exceptional to have that disclosed. It has happened in the past, but it is exceptional.
“That’s why we had a debate in parliament, to say is this the sort of case where it’s so exceptional that it should be disclosed, and at the end of that debate the house could have divided, the government could have voted against it.
“It didn’t, so it can’t come along now and say: ‘We didn’t vote against the order but now we don’t want to comply with it.’”