The changes secured by Theresa May to the Brexit package "reduce the risk" of the UK being held in the backstop, but "the legal risk remains unchanged", according to the British government's attorney general Geoffrey Cox.
In his legal advice to Theresa May's government, Mr Cox warned the UK would have no legal means of exiting without EU agreement.
Mr Cox 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.
A DUP source says they do not see how the party can support the deal following Cox legal advice.
— Hugh O'Connell (@oconnellhugh) March 12, 2019
Game over, it would seem.
"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.
Attorney General confirms that there have been no significant changes to the Withdrawal Agreement despite the legal documents that were agreed last night.
— Keir Starmer (@Keir_Starmer) March 12, 2019
The Government’s strategy is now in tatters. pic.twitter.com/xBKJPy5WbL
"However, the legal risk remains unchanged that if through no such demonstrable failure of either party, but simply because of intractable differences, that situation does arise, the United Kingdom would have, at least while the fundamental circumstances remained the same, no internationally lawful means of exiting the Protocol's arrangements, save by agreement."
Shadow Brexit secretary Sir Keir Starmer quickly responded to Geoffrey Cox's legal advice on the prime minister's Strasbourg agreement.
He tweeted a picture of the document with the last section highlighted in green, which states that the "the legal risk remains unchanged".
Alongside the picture, Mr Starmer said: "Attorney General confirms 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."