Downing Street has insisted that Theresa May's plan to start formal Brexit negotiations by the end of next March will not be derailed by Thursday's High Court decision that she must first secure a vote in parliament.
The court found that the government needs the approval of MPs before triggering article 50 of the Lisbon Treaty, which starts formal exit negotiations.
“The prime minister is clear and determined that this government will deliver on the decision of the British people and take us out of the EU. We are determined to continue with our plan, preparing for negotiations, and sticking to the timetable we set out. We have no intention of letting this decision derail our timetable for triggering article 50,” Downing Street said.
The prime minister’s official spokeswoman said that Ms May will on Friday call European Commission president Jean-Claude Juncker to assure him that she intends to stick to her timetable for starting article 50 negotiations. And the spokeswoman dismissed suggestions that the ruling could prompt the prime minister to call a snap general election, cutting short a parliament due to run until 2020.
Britain’s supreme court will hear an appeal next month but if the high court decision is upheld, Ms May will face serious parliamentary hurdles before she can start formal Brexit talks. Two-thirds of MPs, including a majority of Conservatives, voted against Brexit in the referendum.
Brexit secretary David Davis said he understood the court ruling to mean that an act of parliament would be required to trigger article 50 but he insisted that the referendum in June represented a powerful mandate for Britain to leave the EU.
"The people are the ones Parliament represents – 17.4 million of them, the biggest mandate in history, voted for us to leave the European Union. We are going to deliver on that mandate in the best way possible for the British national interest," he told the BBC.
Shape mandate
MPs are unlikely to try to halt Brexit, but they could seek to shape the government’s negotiating mandate with the EU, limiting its room for manoeuvre on issues such as single market and customs union membership.
The government had argued that it could invoke article 50 without parliamentary approval, using royal prerogative, a set of executive powers. The court found, however, that because article 50 triggers an irreversible process leading to Brexit after two years, it overturns the 1972 European Communities Act, which brought the UK into the Common Market.
“The most fundamental rule of the UK’s constitution is that parliament is sovereign and can make and unmake any law it chooses. As an aspect of the sovereignty of Parliament, it has been established for hundreds of years that the Crown – ie the government of the day – cannot by exercise of prerogative powers override legislation enacted by parliament,” the court said.
The government argued that MPs who passed the 1972 act intended that the Crown should retain its prerogative powers to withdraw from the EU treaties. But the court rejected the argument, saying there was nothing in the 1972 act which supported it. And the judges accepted the main argument against the government, that EU membership conferred rights on UK citizens which the government could not remove without parliamentary approval.
Gina Miller, a fund manager who was the lead claimant in the case, welcomed the decision.
“You can’t have a government casually throwing away people’s rights, that why we turned to the courts. It was the right decision because we were dealing with the sovereignty of parliament. It was not about winning or losing. It was about what was right. Now we can move forward with legal certainty.”
Ukip leader Nigel Farage said he feared “a betrayal” of June’s referendum decision following the court’s decision.
“I now fear that every attempt will be made to block or delay the triggering of article 50. If this is so, they have no idea of the level of public anger they will provoke,” he said.
