BREXIT is a betrayal of the young by the old, who “see Britain as a museum,” Vince Cable will say today as he addresses the tens of thousands of people due to attend a People’s Vote rally in London.

Politicians from across all the main parties will speak at the event, which will be addressed by Nicola Sturgeon via a video link.

Her SNP colleague MP Joanna Cherry will speak on the stage alongside Sadiq Khan, the London Mayor, his Labour colleague Chuka Umunna, Conservative Anna Soubry and the Greens’ Caroline Lucas.

Sir Vince, the Liberal Democrat leader, will also speak and is due to say: "Tragically, Brexit divides one generation from another. A substantial majority of my generation voted to leave. A substantial majority of the young voted to remain. Your generation is being betrayed by mine. By those who look to the past, who see Britain as a museum."

Fellow People’s Vote campaigner Labour's Lord Adonis, said: "Brexit's becoming a dog's dinner.

"This week's fresh chaos and confusion over Brexit negotiations has exposed how even the best deal now available will be a bad one for Britain.

"It's a mess that nobody voted for and the reason we're in such a growing crisis is that those cheerleading for Brexit know the promises they made can never be kept.”

The former minister said the campaign was about using people power to address the wrongs of a botched Brexit process.

"This is about making sure MPs understand how strong feelings are running on this vital issue. If they are wavering, they need to know there is a political price to be paid for doing the wrong thing.

"Voters will neither forgive nor forget if MPs allow this miserable Brexit to proceed without people being given the final say," added the peer.

Among the celebrities attending the event will be celebrity cook Delia Smith, Dragons' Den businesswoman Deborah Meaden. The rally is being compered by broadcasters Richard Bacon and Mariella Frostrup.

Video messages will be played from comedians Mitch Benn and Patrick Kielty as well as former footballer Gary Lineker.

As part of the campaign, called #WriteThisWrong, 100,000 postcards will be distributed which have been imprinted with the words: “Brexit has already become a dog’s dinner. The whole process is going badly wrong. And it’s only going to get worse.”

Some 150 coachloads of people from across the country are expected to head to the march, with around 30 vehicles sponsored by famous names including football manager Alan Pardew, actor Natascha McElhone, writer Armando Iannucci, former footballer Jamie Carragher and singer Olly Alexander.

The march will begin at midday in Park Lane before the rally take place in Parliament Square.