LONDON  -  Tens of thousands are marching through central London calling for another EU referendum, as MPs search for a way out of the Brexit impasse. Demonstrators from the “Put It To The People” campaign are marching from Park Lane to Parliament Square, before rallying in front of Parliament.

It comes after the EU agreed to delay the UK’s departure from the EU.

PM Theresa May has said she will ditch plans for another vote on her Brexit deal if not enough MPs support it.

Unless that deal is passed by MPs, the UK will have to come up with an alternative plan or else face leaving without a deal on 12 April.

London Mayor Sadiq Khan tweeted a video of himself joining demonstrators holding up a ‘Put it to the People’ banner at the front of the march as it began.

He was flanked at the front of the march by Liberal Democrat leader Vince Cable, who tweeted that there was a “huge turnout of people here from all walks of life”.

Meanwhile, a record-breaking online petition on Parliament’s website calling for Brexit to be cancelled by revoking Article 50 has attracted more than 4.3 million signatures.

Liberal Democrat MP Layla Moran said the petition could “give oxygen” to the campaign for another Brexit referendum. Mr Watson is expected to promise to back Mrs May’s deal if she agrees to hold a referendum on it. He is expected to say: “I’ve come to the reluctant view that the only way to resolve this and have legitimacy in the eyes of the public is for the people themselves to sign it off.”

Ms Soubry told the BBC: “It’s good to see Tom Watson coming on the march today... I honestly believe it’s the only way forward.” She added: “It’s intolerable the situation that we’re in and I’m afraid Theresa’s the problem.

“I’m not saying the government should go because that’s the last thing we want, but I think she has to go and we need some temporary prime minister who can reach out, put the country first, get this back to the British people - that’s what we’re all marching for today, a people’s vote.”