Former Labour and Change UK MP Chuka Umunna has joined the Liberal Democrats.
The one-time shadow business secretary announced the news on Thursday night in what will be seen as a boost for Sir Vince Cable’s party.
He said: “I’m delighted to say I’ve joined the @LibDems!”
It is expected Umunna will appear with Lib Dem leader Cable for a press conference on Friday.
Speaking to the Times, Umunna said the Liberal Democrats were “at the forefront” of “a progressive and internationalist movement” in British politics.
He said: “Labour and the Tories are committed to facilitating Brexit, and Brexit makes ending austerity virtually impossible.
“The Liberal Democrats are not - they were arguing for a People’s Vote and to remain in the EU from the very start.
“I am convinced the Liberal Democrats, as the spearhead of a broader progressive movement in civil society, offer the best chance to improve the lives of those I represent as well as countless other citizens across our country.”
Umunna was among seven Labour MPs to dramatically split from Jeremy Corbyn’s party to form the Independent Group, later known as Change UK, in February.
After just four months, however, six MPs, including Umunna, left the new party and confirmed they would sit as independent MPs.
The split followed disappointing election results, where Change UK failed to make major gains but the Lib Dems came second after the Brexit Party.
Heidi Allen, Luciana Berger, Sarah Wollaston, Gavin Shuker and Angela Smith were among the others who left the fledgling party.
Outgoing Lib Dem leader Cable has welcomed Umunna into the fold.
He said: “Chuka and I have worked together effectively for many months, campaigning for a People’s Vote and to Stop Brexit.
“I know that he will be a great asset to our party not just on Brexit, but in fighting for the liberal and social democratic values that we share.
“He joins alongside 20,000 people across the country just this month, demonstrating clearly that the Liberal Democrats are the biggest, clearest and most formidable force in the liberal centre-ground of British politics today.”
Former Liberal Democrat leader Tim Farron tweeted: “Fantastic news. Welcome Chuka!”
Sir Ed Davey and Jo Swinson are currently battling it out in the contest to replace Cable as leader.