A spokesperson for the People’s Vote campaign said: “It is up to MPs what amendments they table and when. A People’s Vote will probably not secure a majority in the House of Commons until every Brexit option has been exhausted but that there will be multiple opportunities in Parliament to give the public the final say when it has become clear this is the only way forward.”

The second significant split within People’s Vote is over whether it should attempt to run the Remain campaign if there is a second referendum.

The campaign’s data, which according to two sources includes an email list of more than 750,000 people, is held by Open Britain, the successor to Britain Stronger in Europe, the official Remain campaign at the 2016 referendum.

Many senior figures at People’s Vote believe they should lead the Remain campaign at a second vote. “It would be inconceivable that a lot of the same people would not be involved,” one said.

But other second referendum campaigners are adamant that the politicians and strategists at People’s Vote should not be anywhere near another Remain campaign. “There is absolutely no way the Blairite faction can be allowed to run the campaign at a second referendum,” said one prominent pro-Remain campaigner for a public vote, adding: “We’d lose 70–30.”

An official on the People’s Vote campaign agreed: “The next Remain campaign would have to be broader and not led by MPs. But there is obviously a difference of opinion over that.”

The day-to-day activities of People’s Vote MPs have also caused tensions. A Conservative source said the launch of a new second referendum campaign called Right to Vote by Tory MPs Philip Lee, Heidi Allen, and Sam Gyimah last week was not approved by People’s Vote. They said it was viewed as hubristic on the part of Lee. The source added that there has been a breakdown of control within the campaign and questions internally about its strategy in recent weeks.

Meanwhile, the decision last week of 71 Labour MPs to announce their support for a second referendum at an event attended by only 36 MPs infuriated senior campaign officials, who felt that publicly revealing how few Labour MPs back the campaign was a strategic blunder.

Another fissure has emerged over the future of the campaign after a second referendum. According to several campaign sources, a number of People’s Vote MPs see it as a vehicle for setting up a new centrist party.