Six of Change UK’s 11 MPs, including its spokesman, Chuka Umunna, and interim leader Heidi Allen, have abandoned the fledgling party after its dire performance at the European elections.
The party announced that a new party leader, Anna Soubry, had been elected.
She said she was “deeply disappointed” that Heidi Allen, Chuka Umunna, Sarah Wollaston, Angela Smith, Luciana Berger and Gavin Shuker had left.
The departing MPs said they would be “returning to supporting each other as an independent grouping of MPs”.
The others remaining are the former Labour MPs Mike Gapes, Chris Leslie, Joan Ryan and Ann Coffey.
In a statement, Soubry said: “I’m deeply disappointed that at such a crucial time in British politics our former colleagues have made this decision.
“Now is not the time to walk away, but instead to roll up our sleeves and stand up for the sensible mainstream centre ground which is unrepresented in British politics today.
“Going forward, the Change UK MPs are as determined to fix Britain’s broken politics as we were when we left our former parties.”
None of the departing MPs are defecting immediately to the resurgent Liberal Democrats; but party sources said they expected some to do so in the future.
Both Allen and Umunna have been advocating closer cooperation with the Lib Dems.