Brexit legal challenge wins: MPs could delay leaving EU until after 2020, says top constitutional lawyer

Geoffrey Robertson QC, who predicted Theresa May would need parliamentary approval to trigger Article 50, says MPs could prevent Brexit until after next election if they have 'guts and integrity'

Brexit will now be delayed until after the next election if parliament has the “guts and integrity” to insist on a second referendum, according to a leading lawyer who predicted Theresa May would not be legally allowed to trigger Article 50 without allowing MPs and peers to vote.

Geoffrey Robertson QC said the High Court’s decision – that the Prime Minister could not use the Royal Prerogative to begin the process of leaving the European Union – was both “correct and obvious”, adding he expected the Supreme Court would reject the Government’s planned appeal.

Ironically, Ms May could then take her case to the European Court of Justice.

Mr Robertson said the fact there was a dispute over the mechanism by which the UK could make such an important decision showed why it should have a formal, written constitution.

“Today’s judgement emphasises that democracy means representative democracy and it is for MPs, voting according to their consciences and what they think is good for the country, to take us out of a constitutional arrangement that they took us into 40 years ago,” he said, quipping "well, I was right" after earlier insisting parliament would have to be consulted.

“I expect the Supreme Court will uphold today’s decision, which in my view is correct and obvious.

“If MPs have any guts and integrity, they will vote against Brexit until there has been a second referendum.

“I expect the House of Lords will certainly do this, so that Brexit, if it ever happens, will be delayed probably until after the 2020 election.”

According to the law which created the EU referendum, the decision was not binding on parliament.

“The referendum was merely advisory – 37 per cent voted to Leave, 35 per cent to remain and 28 per cent didn’t think it important enough to vote at all,” Mr Robertson said.

“They may now be having serious second thoughts as Brexit threatens to ruin the economy and the social structure.”

He pointed out how unusual the UK was in not having a written constitution.

“Britain is the only country in the world, other than Saudi Arabia, which does not have a written constitution and this [legal dispute] explains exactly why it should,” he said.

Nicholas Evans, a partner at Bircham Dyson Bell, said the High Court’s ruling would not stop the process of leaving the EU, “but it makes clear who has the power to start that process” and would at least delay Ms May’s plans.

“The courts have decided that the Government has no power to start the process without an Act of Parliament, holding that it is ‘not plausible to suppose’ that the Crown could ‘switch off’ the direct effect of EU law by its own unilateral action,” he said.

“This finding that a Parliamentary Act is needed to trigger article 50, will seriously jeopardise the Prime Minister’s plan to start the process next March.”

Mr Evans also noted the High Court ruling’s wider implications. “This significant decision fills in another part of our unwritten constitution,” he said.

Clive Thorne, a partner at law firm Wedlake Bell, echoed that point, saying the ruling was “of profound political and constitutional consequence”.

“The application against the Government to the effect that it cannot implement article 50 of the treaty by means of the royal prerogative has been accepted on the basis that the European Communities Act 1972 effectively prevents the Government relying on its prerogative powers to effect withdrawal from the EU treaties and that therefore the Government does not have the power to give notice under article 50 without legislation and amending the 1972 act,” he said.

“The Government is now appealing to the Supreme Court to overrule this decision. If this decision is not overruled, then Parliament will have to pass rapid legislation to amend the 1972 Act and permit the Government to proceed with article 50.”