The Attorney General said additions to the Brexit deal secured by the Prime Minister in last-minute talks with the EU on Monday night “reduce the risk” of the insurance policy for the Irish border in the vent that Brussels acts with “bad faith or want of best endeavours” in negotiations on a future trade deal.
However, he said the situation was unchanged if a deal that supersedes the backstop cannot be reached “through no such demonstrable failure of either party”.
Speaking to journalists shortly before the legal advice was released, Tory MP Mark Francois, the deputy chairman of the European Research Group of Brexiteers, said Mr Cox’s legal advice would “have to be pretty amazing” to convince him to back the deal.
Commenting on the Strasbourg agreements, the Attorney General wrote: "I now consider that the legally binding provisions of the Joint Instrument and the content of the Unilateral Declaration reduce the risk that the United Kingdom could be indefinitely and involuntarily detained within the Protocol's provisions at least in so far as that situation had been brought about by the bad faith or want of best endeavours of the EU.
"It may be thought that if both parties deploy a sincere desire to reach agreement and the necessary diligence, flexibility and goodwill implied by the amplified duties set out in the Joint Instrument, it is highly unlikely that a satisfactory subsequent agreement to replace the Protocol will not be concluded.
"But as I have previously advised, that is a political judgment, which, given the mutual incentives of the parties and the available options and competing risks, I remain strongly of the view it is right to make.
Shadow Brexit secretary Sir Keir Starmer said: “The Attorney General has confirmed that there have been no significant changes to the Withdrawal Agreement despite the legal documents that were agreed last night.
“The Government’s strategy is now in tatters.”