Brexit legal advice: No way out of the backstop without a trade deal

The UK will be locked in a customs union with the EU even if other ways of avoiding a hard border with Ireland are found, according to the government’s top lawyer.

The secret legal advice given by the Attorney General to the Cabinet on the proposed Brexit deal makes it clear the UK would struggle to end the backstop plan using “alternative arrangements”.

The advice, published today after a battle in Parliament, reveals the Attorney General Geoffrey Cox believes the only way out of the backstop is with a trade deal.

Cox warns that even if talks between the UK and EU break down, it would be difficult to convince a proposed arbitration panel of alternative ways of keeping the border invisible.

The letter, sent to the Prime Minister on November 13, reads: “The current drafting of the Protocol, including Article 19, does not provide for a mechanism that is likely to enable the UK lawfully to exit the UK wide customs union without a subsequent agreement.

"This remains the case even if parties are still negotiating many years later, and if the parties believe that talks have clearly broken down and there is no prospect of a future relationship agreement.

"The resolution of such a stalemate would have to be political.”

In a paragraph likely to enrage the DUP, which theoretically props up Theresa May’s government, Cox set out the true implications of the backstop agreement on the relationship between Northern Ireland and Great Britain.

He wrote: “The implications of NI remaining in the EU Single Market for Goods, while GB is not, is that for regulatory purposes GB is essentially treated as a third country by NI for goods passing from GB into NI. This means regulatory checks would have to take place between NI and GB, normally at airports or ports, although the EU now accepts that many of these could be conducted away from the border.”

DUP MP Nigel Dodds, who leads his party in Westminster, described the legal advice as "devastating".

Labour's shadow Brexit secretary Sir Keir Starmer, who led the charge to get the advice made public in spite of claims it was not in the public interest, said: "All this advice reveals is the central weaknesses in the Government’s deal."