Liberal Democrat MPs will vote against triggering Article 50 unless the government promises to hold a second referendum, the party's leader Tim Farron said today.
Farron wants a public vote on any final deal on the UK's membership of the EU, and said Lib Dem MPs would vote against enacting the legislation required to kick off the Brexit process if this demand isn't granted.
Theresa May has already ruled out another referendum on EU membership.
"We'd vote against Article 50 if our 'red line' is not met ... which is we want to respect the will of the people and that means they must have their say on a referendum on the terms of the deal," he told BBC radio.
There are currently eight Lib Dem MPs in parliament.
"We believe that what started with democracy last June, which we totally respect, must not now end up with a stitch up, with a deal being imposed on the British people that absolutely nobody voted for," said Farron.
Several Labour MPs have also said they would vote against enacting Article 50.
Junior Brexit minister David Jones said: "Because they didn't like the first answer, Liberal Democrat and Labour MPs seek to put the question all over again in hope of a different answer."