Lib Dems give Theresa May ultimatum: No second referendum, no Article 50

The Liberal Democrats lay out their Brexit red line, insisting the British public must decide on the terms of any Brussels deal.

Remain voters protest against Brexit
Image: Theresa May faces efforts to derail her Brexit process
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The Lib Dems have threatened to block an Article 50 vote on starting EU divorce proceedings if Theresa May does not agree to put the terms of a Brexit deal to the public in a second referendum.

Leader Tim Farron issued the ultimatum ahead of the Government appeal against a High Court ruling that the Prime Minister does not have the power to trigger Article 50 without putting it before Parliament.

While the party only has eight MPs, it does have more than 100 peers in the House of Lords and this could mean trouble for Mrs May if she has to put the EU exit trigger to the vote.

Mr Farron accused the Government of having no plan for Brexit, saying: "Millions of people are deeply worried by the Government's handling of Brexit. 

"So my position is very clear: the Liberal Democrats believe that the people are sovereign.

"They must decide whether or not they agree with the deal that the Government reaches with Brussels, which means a referendum at the end of the negotiations where people can either vote for the deal or to remain in Europe.

"We will vote against Article 50 unless it allows the people a vote on the deal, because the will of the people must prevail - both on departure and destination."

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Shadow Brexit Minister on Article 50 and the courts

Labour has said it will not block Article 50, however in an interview on Sky News last week the shadow Brexit secretary, Sir Keir Starmer, said the party wanted to see the Brexit plan first.

He said that MPs could not be expected to vote on whether to trigger the divorce process with the EU "in a vacuum" and said the Government "must put its plans before Parliament".

SNP leader Nicola Sturgeon has said her 54 MPs would "certainly not vote for anything that undermines the will or the interests of the Scottish people".

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Sturgeon: Scotland's wishes 'cannot be brushed aside'

Scotland has applied to join the case at the Supreme Court against the Government appeal and has said it wants Article 50 voted on in Parliament and in Holyrood.

Mrs May has insisted the Government has a "strong case" and argues she can use power under the Crown's prerogative to trigger Article 50 without consulting MPs and peers.

The Prime Minister has insisted she will meet the end of March deadline she has set out to formally notify the EU that the UK is leaving, thereby setting off the two-year negotiation process.

While she has yet to set out a Brexit plan, Mrs May has insisted "Brexit means Brexit" and made it clear that immigration is at the top of her list.

She has also talked about the "fullest possible access to the single market".

However, she has said there will be "no running commentary" on the process, leading MPs on all sides to criticise the Government for a lack of transparency.