The UK Supreme Court has ruled that Prime Minister Theresa May must get Parliament’s approval before she begins Britain’s formal exit from the European Union.

The British government has said in response it will introduce “straightforward” legislation within days, seeking parliament’s approval to trigger the divorce.

Brexit minister David Davis said the bill will be the most straightforward possible “to give effect to the decision of the people and respect the Supreme Court’s judgement.”

Davis has categorically ruled out the prospect of a second EU referendum as he said he would not back another poll “under any circumstances”.

The Brexit Secretary said arguments in favour of another referendum on the grounds that people did not know exactly what they were voting for on June 23 last year are “patronising” and “undemocratic”.

The UK’s highest judicial body dismissed the government’s argument that Mrs May could simply use executive powers known as “royal prerogative” to invoke Article 50 of the EU’s Lisbon Treaty and begin two years of divorce talks.

However, the court rejected arguments that the UK’s devolved assemblies in Northern Ireland, Scotland and Wales should give their assent before Article 50 is invoked.

“The referendum is of great political significance, but the Act of Parliament which established it did not say what should happen as a result,” said David Neuberger, President of the Supreme Court which ruled by 8-3 against the government.

“So any change in the law to give effect to the referendum must be made in the only way permitted by the UK constitution, namely by an Act of Parliament.”

Mrs May has repeatedly said she would trigger Article 50 before the end of March but she will now have to seek the consent of lawmakers first, potentially meaning her plans could be amended or delayed, although the main opposition Labour Party has said it would not slow her timetable.

Last week Mrs May set out her stall for negotiations, promising a clean break with the world’s largest trading block as part of a 12-point plan to focus on global free trade deals, setting out a course for a so-called “hard Brexit”.

UK parliament must approve start of Brexit process, Supreme Court rules https://t.co/cTwfh1zKos pic.twitter.com/Jhdcgy2bzZ

— RTÉ News (@rtenews) January 24, 2017