A British high court has ruled that Parliament must vote on whether the UK can start the process of leaving the European Union (EU).
The decision is a significant blow to UK Prime Minister Theresa May, who had planned to begin formal exit negotiations by the end of March by triggering Article 50 of the Lisbon Treaty.
The government is now appealing the decision at the Supreme Court, and another hearing is expected next month.
Ms May says the Brexit referendum means MPs don't need to vote.
Brexit Secretary David Davis says that Parliament represents the British people - and they've already made their decision.
"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.
But the opposition Labour Party says the court ruling highlights the need for greater transparency on the terms of Brexit.
"This ruling underlines the need for the government to bring its negotiating terms to parliament without delay," says Labour leader Jeremy Corbyn.
"Labour respects the decision of the British people to leave the European Union. But there must be transparency and accountability to Parliament on the terms of Brexit."
Scotland's First Minister Nicola Sturgeon said the "hugely significant" ruling reveals the "chaos and confusion" at the heart of the British government over the vote to leave.
"We should remember that their refusal to allow a vote in the House of Commons is not because of some matter of high constitutional principle, it is because they don't have a coherent position and they know that if they take their case to the [chamber] that will be exposed," she told the devolved Scottish Parliament.
"[Scottish National Party lawmakers] will certainly not vote for anything that undermines the will or the interests of the Scottish people."
Meanwhile, a new BMG Research poll reveals the British electorate would now vote to stay in the EU.
In the June 23 referendum, 51.9 percent of Britons voted to leave, while 48.1 percent voted to remain.
In the new poll, though, 45 percent opted to remain, 43 percent opted to leave and 12 percent did not know.
"Rather than people switching to Remain, it looks as if people are now less decisive about whether it was the right decision to leave," Michael Turner, head of research at BMG, told Reuters.
The fieldwork was conducted from October 19 to 24 among 1546 adult UK residents.
Reuters / Newshub.