An attempt to rule Boris Johnson’s Brexit deal as unlawful and attempting to prevent it being voted on by MPs is set to be heard at Scotland’s highest civil court.
Campaigner Jolyon Maugham QC is behind the legal challenge which will be heard at the Court of Session in Edinburgh.
He argues the new deal contravenes a current law stipulating it is “unlawful for her majesty’s government to enter into arrangements under which Northern Ireland forms part of a separate customs territory to Great Britain”.
This part of the Taxation (Cross-border Trade) Act 2018, Section 55, was put forward by the Conservatives’ right-wing group of MPs known as the European Research Group (ERG).
Changes to the agreements around Northern Ireland were a key part of the new Brexit deal agreed between the government and the EU this week.
The prime minister tweeted it removes the “anti-democratic” Irish backstop.
The EU’s chief negotiator Michel Barnier said under the new agreement Northern Ireland would be part of the UK’s customs territory, not the EU’s, but would “remain an entry point” into the EU single market and aligned to some EU rules on goods.
This means they must be checked on entry to the island of Ireland, rather than border checks between Northern Ireland and the Republic.
Maugham, whose legal team earlier took legal action to try to prevent a no-deal Brexit by ensuring the prime minister obeys by the Benn Act, is seeking a court order, or interdict, banning the government from putting the new deal before parliament for a vote on Saturday.
He tweeted: “We do not understand how the government might have come to negotiate a Withdrawal Agreement in terms that breach amendments tabled by its own European Research Group.
“Unless and until Section 55 is repealed by the UK parliament, it is simply not open, as a matter of law, for the United Kingdom to enter into such an agreement.”
He said if the court rules the new deal is “unlawful”, the government will have to request a Brexit extension.
Maugham added: “If the government wants to seek parliament’s consent to repeal section 55, it can and should seek that consent.
“But it must not negotiate unlawful trade deals and then present them to Parliament as a fait accompli.”