A major push for a “people’s vote” on the final Brexit deal between Britain and the EU has been launched by MPs, celebrities and business leaders. A cross-party lineup of MPs took to the stage at the Electric Ballroom in Camden, north London, on Sunday. They have been at pains to avoid the term “second referendum”.

The MPs included Conservative Anna Soubry, Labour’s Chuka Umunna, the Greens’ Caroline Lucas and Liberal Democrat Layla Moran.

“We have got to get a majority in the House of Commons for the proposition of this people’s vote,” Umunna told a crowd of more than 1,000 people, many of whom were waving flags and sporting remainer garb ranging from blue berets to stickers proclaiming “Bollocks to Brexit”. “That means at the very least my party, the Labour party, needs to be true to its values and support this,” he added, eliciting foot-stomping and cheering from the crowd.

In the audience, meanwhile, participants such as business consultant Peter Cook shrugged about the optics of holding such a key anti-Brexit event in the arch-remainer territory of north London. “We have taken the easy way in terms of doing this in north London, yes, but the reality of what we’re saying is still unavoidable,” said Cook.

“What we do have to do, though, is get out there in the Brexit heartlands – places like Clacton and Ramsgate and Sunderland. I’ve been punched in Brexitland, and I can tell you that it hurts, but we have to go there.”

Outside, a few dozen pro-Brexit supporters had staged a counter-protest, greeting the queue of remainers with placards bearing slogans such as “Full Mettle Brexit Now”. “We know that they’re going to be calling for a second referendum, which they will dress up as something else. We believe that a vote has already happened,” said Lucy Harris, one of the organisers of the counter protest.

Their picket had, she said, been guided by “leavers of London” and had brought together supporters of all parties and none. Behind her, two members of the Communist party of Britain (Marxist-Leninist) handed out leaflets urging: “Take Control”.

On the sidelines, passionate but respectful discussions were taking place between supporters of either side. “We have much more in common than what divides us, but it’s still fear of the unknown that makes people want to remain,” said Londoner Patrick Leonard, wearing a black T-shirt emblazoned with the word “Brexiteer”.

In reply, Chevan Ilangaratne was confident that the people’s vote campaign would touch a nerve. “This is just the beginning and we know what we have to do,” he said.

“When Mrs May has finished her negotiations, it’s going to be obvious that people should have the right to have a vote on the final deal.”