A majority of Supreme Court judges have ruled that MPs and peers must authorise the use of Article 50 – the legal step that triggers Brexit.
In theory this ruling could plunge the entire Brexit process into chaos if enough MPs and peers vote against invoking Article 50.
But the Government is counting on the support of most politicians in order to push a short bill through Parliament quickly.
Theresa May needs to get the bill approved very quickly if she is going to trigger Article 50 and begin exit talks before the end of March.
The odds of Mrs May not triggering Article 50 by the end of March are 4/6, according to bookmaker Paddy Power.
Satirical artist Kaya Mar poses with one of his paintings outside the Supreme Court
A Paddy Power said: “The Prime Minister will need to get her plans past the two Houses of Parliament first, though – Paddy Power make it 4/1 that she’s vetoed.”
Labour leader Jeremy Corbyn said Labour will seek to amend the bill, but “will not frustrate the process for invoking Article 50”.
Shadow Brexit secretary Keir Starmer said: “We don’t seek to block the Prime Minister from starting negotiations.
“But we have said all along that the terms of the negotiations and the role of parliament in this is really important. So we will be pushing for amendments.”
Liberal Democrat leader Tim Farron said: “We demand a vote of the people on the final deal and without that we will not vote for Article 50.”
The SNP have suggested that the party could proposes as many as 50 amendments. Alex Salmond added: “Consultation must mean consultation.”
BREXIT: Supreme Court Ruling
Tue, January 24, 2017
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Britain's most senior judges ruled that Prime Minister Theresa May does not have the power to trigger the formal process Article 50 for the UK's exit from the European Union without Parliament having a say.
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Lead claimant in the Article 50 case, Gina Miller delivers a statement outside the Supreme Court in London
Conservative MP Ken Clarke has told his constituents that he may be the only Conservative MP to vote against Article 50.