The former Tory MP Heidi Allen, who quit the fledgling party Change UK after four months, has announced that independent MPs will form another new parliamentary group, to be known as The Independents.

Allen said the new group would be a cooperative and she would be coordinating a “remain alliance” of parties against Brexit.

Allen left the Conservatives to join the Independent Group, led the successor political party Change UK, which formed for the EU elections, and then quit after a disastrous set of results.

The MPs have been through a series of shakeups, both as a collective and in separate groups. At one point they registered with the Electoral Commission as the Independent Group for Change.

Allen had been tipped to follow another former Change UK MP, Chuka Umunna, in joining the Liberal Democrats, but on Wednesday she said she and others who had quit the party would remain independent and focus their efforts on forming an anti-Brexit alliance of different parties.

“The Independents is the new home for independent politicians in Westminster,” the cooperative said in a statement, adding that it was not a political party and wanted to work across party lines.

“It launches today to encourage a stronger spirit of cross-party working and its members will work collaboratively in the national interest, including to prevent a damaging no-deal Brexit which will put the jobs and futures of young people of this country at risk.”

Allen will launch a group called Unite to Remain, which she said would work with the Lib Dems, Greens, Change UK, Plaid Cymru and the remainder of Change UK in order to ensure the anti-Brexit vote was not split.

She said the grouping had been formed because of the increasing likelihood of a snap general election, should Boris Johnson attempt to force through a no-deal Brexit in the autumn.

The movement, which Allen said was not a new political party, will conduct a seat-by-seat analysis and encourage the parties to step aside to support whichever has the best chance of winning. It hopes to form an alliance for between 150 and 180 seats across the country, though the Scottish National party has declined to take part.

The independent grouping will also include the former Labour MPs Luciana Berger, Gavin Shuker and Angela Smith, who all quit Change UK.

The MP John Woodcock, who left the Labour party while under investigation for harassment, said he hoped to join the group and said he had offered to have the complaint against him investigated under its new procedures.

Woodcock is a critic of Jeremy Corbyn and has said he did not believe he would be subject to a fair process by Labour. He tweeted on Wednesday: “I strongly deny the charge and said when I left Labour that I was committed to finding a way to get a fair hearing for both sides that had been denied by the party’s corrupted internal processes which are failing both complainants and those accused.”