The UK Supreme Court this morning ruled that the government of British Prime Minister Theresa May cannot initiate talks with Brussels about the kingdom’s withdrawal from the European Union without a vote from Parliament authorizing such negotiation under Article 50 of the Lisbon treaty. Just Security will have in-depth analysis of the 96-page ruling later today, but a few key details stand out.

The court ruled that Parliament must vote on Brexit talks because a withdrawal from EU law will impact legal rights in Britain and as such, must be authorized by lawmakers.

Per the BBC, UK Supreme Court President Lord Neuberger said while reading the judgment aloud:

“By a majority of eight to three, the Supreme Court today rules that the government cannot trigger Article 50 without an act of Parliament authorising it to do so.”

He added: “Withdrawal effects a fundamental change by cutting off the source of EU law, as well as changing legal rights.

“The UK’s constitutional arrangements require such changes to be clearly authorised by Parliament.”

Meanwhile, British government officials are insisting that the ruling won’t delay Brexit talks, slated to begin by March 31, with Parliament’s Brexit Secretary, William Davis, promising to have a bill before MPs on the matter within days, according to the BBC:

Outlining plans to bring in a “straightforward” parliamentary bill on Article 50, Mr Davis told MPs he was “determined” Brexit would go ahead as voted for in last June’s EU membership referendum.

He added: “It’s not about whether the UK should leave the European Union. That decision has already been made by people in the United Kingdom.”

“There can be no turning back,” he said. “The point of no return was passed on 23 June last year.”

Outside the Supreme Court, Attorney General Jeremy Wright said the government was “disappointed” but would “comply” and do “all that is necessary” to implement the court’s judgement.

A Downing Street spokesman said: “The British people voted to leave the EU, and the government will deliver on their verdict – triggering Article 50, as planned, by the end of March. Today’s ruling does nothing to change that.”

Foreign Secretary Boris Johnson, a leading Leave campaigner, tweeted: “Supreme Court has spoken. Now Parliament must deliver will of the people – we will trigger A50 by end of March. Forward we go!”

Opposition party members meanwhile say they will work to prevent the vote from being used to pass a simple rubber stamp bill authorizing withdrawal talks. A spokesman for Labour Party leader Jeremy Corbyn issued a statement reading: 

Labour respects the result of the referendum and the will of the British people and will not frustrate the process for invoking article 50.

However, Labour will seek to amend the article 50 bill to prevent the Conservatives using Brexit to turn Britain into a bargain basement tax haven off the coast of Europe.

Labour will seek to build in the principles of full, tariff-free access to the single market and maintenance of workers’ rights and social and environmental protections.

Labour is demanding a plan from the government to ensure it is accountable to parliament throughout the negotiations and a meaningful vote to ensure the final deal is given parliamentary approval.

The BBC on Twitter also quoted Shadow Brexit Secretary, Keir Starmer, as saying the “government needs to publish plan for parliamentary scrutiny – speeches are not enough.”

It’s also worth nothing that the court ruled that the parliaments of Scotland and Northern Ireland don’t have a say in authorizing withdrawal talks. With the court’s press summary of the judgment reading:”Relations with the EU and other foreign affairs matters are reserved to UK Government and parliament, not to” the legislatures of Scotland or Northern Ireland.