Brexit march: Labour's most senior figures break with Jeremy Corbyn to declare it is now a Remain party

Chants of ‘Where’s Jeremy Corbyn?’ as all of party’s senior figures applauded at Final Say rally – except its leader

Jeremy Corbyn’s three most senior colleagues broke with their leader to declare Labour a Remain party – earning them cheers at the giant Westminster rally for a Final Say referendum on Brexit.

John McDonnell, the shadow chancellor, Diane Abbott, the shadow home secretary, and Emily Thornberry, the shadow foreign secretary, all made clear Labour’s determination to keep the UK in the European Union.

The speeches prompted chants of “Where’s Jeremy Corbyn?” – to the tune of The White Stripes’ Seven Nation Army, the very chant that symbolised his shock resurgence at the 2017 general election.

The Labour leader, who has suggested he will sit on the fence if the referendum is held, chose not to walk the few yards from the Houses of Parliament to address the rally.

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Meanwhile, former Conservative Antoinette Sandbach, whom Boris Johnson would have hoped to woo to back his deal in next week’s vote, declared her continued support for a fresh public vote.

“When the time comes to support a People’s Vote amendment, I can walk through that lobby with my head held high,” said the MP, currently sitting as an independent.

The speeches were put on hold for the dramatic moment when the result of the Letwin amendment was declared – frustrating Boris Johnson’s hopes of passing his deal – which was greeted with huge cheers.

Labour’s big-hitters arrived soon afterwards, Ms Abbott telling the gathering in parliament square: “I’m a Remainer.”

Ms Thornberry said: “We are internationalists, we are Europeans and we want to stay that way,” adding: “Labour is a Remain party and later we will prove that this is a Remain country.”

And Mr McDonnell, Mr Corbyn’s closest ally, told the crowd that Labour was now committed to staying in the EU, saying: “We believe that our future best lies within the European Union itself.”

Keir Starmer, Labour’s Brexit spokesperson, said the only way to break the impasse was a referendum on the latest deal, adding: “When we get to that vote, we need to fight for Remain.”

A year ago, it would have been unthinkable for Labour’s top team to declare their support for EU membership at a Final Say rally, reflecting the huge shift in the party’s thinking.

They now believe the only way for Mr Corbyn to win an election is by settling the Brexit issue first, at a referendum when Labour will fight for Remain.

Earlier, Star Trek actor Patrick Stewart praised the crowd for proving a second referendum was not the “pipe dream” or “moon shot” that it was seen as when the campaign began.

He remembered how it had begun for him in “an old night club in Camden”, in North London, saying: “You haven't just filled a nice bar in north London, you have taken over an entire city.

“You haven't just impacted the Brexit debate, you have transformed British politics.”

And Great British Bake Off presenter Sandi Toksvig likened the Brexit deal on offer to a rickety old car, with the door missing entirely on the passenger’s side.

“I’m not buying a car that puts my family in danger,” she vowed – before leading the crowd on a chant of “hear us” directed at the politicians across the square.