Britain would be trapped “indefinitely” in a customs union with Brussels if MPs back Theresa May’s Brexit deal, according to leaked details of the attorney-general’s legal advice, which the government has suppressed.
Senior ministers say the prime minister is refusing to publish the advice because it contains a stark passage that makes clear the UK could end up locked in a “backstop” arrangement with the European Union.
In a letter to cabinet ministers last month, the contents of which have been disclosed to The Sunday Times, Geoffrey Cox declared: “The protocol would endure indefinitely.” The government’s top law officer ruled that the only way Britain could escape the backstop would be to sign a new trade deal, which could take years. But he warned Britain could remain trapped if those talks collapsed.
The details — confirmed by three serving cabinet ministers and the former Brexit secretary Dominic Raab — will enrage Eurosceptics and are likely to harden opposition to the deal. More than 100 Tory MPs have already signalled they will oppose their own government in the crunch vote on December 11 that has left May’s premiership hanging by a thread.
Tomorrow Cox will give a statement to parliament outlining the government’s legal position in an effort to win over MPs. No 10 is expected to publish a summary of the advice but not the letter itself — a move senior ministers believe will lead to the Speaker, John Bercow, declaring the government in contempt of parliament.
Ministers say the written legal advice is far bleaker than the account Cox will give in the Commons and the verbal assessment he gave the cabinet in October. A cabinet source said: “The legal advice is very bad, which is why they don’t want anyone to see it.”
Cox’s letter was so sensitive that numbered copies of the paper were taken from ministers after they had read it. “The letter was not allowed to leave the room,” a minister said.
Raab, who resigned as Brexit secretary last month, confirmed: “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 The backstop will last indefinitely, until it is superseded by the treaty setting out our future relationship, unless the EU allows us to exit.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 the formal advice I received.”
