Luciana Berger has joined the Liberal Democrats after a brief stint as an independent MP.
The former Labour and Independent Group politician said the Lib Dems were the “strongest party to stop Brexit, fight for equality and a fairer country”.
“The Liberal Democrats today best represent my values and are unequivocal in wanting to stop Brexit and are committed to securing Britain’s future as a tolerant, open and inclusive society” she said.
Ms Berger also used the announcement to attack the Labour Party, calling it “institutionally antisemitic, overtaken by the far left and consumed by a Brexiteer leadership”.
It was her third change in party this year - she quit Labour in February to form the Independent Group of MPs, however she left this party in June to sit as an independent.
In July, Ms Berger addressed media reports she planned to follow former Independent Group MP Chuka Umunna in joining the Lib Dems, claiming she had “no intention” of joining the party.
Party leader Jo Swinson said she was “delighted and proud” to welcome Ms Berger and was looking forward to “working together to stop Brexit".
She was the second MP to join the Liberal Democrats in recent days – former Conservative Dr Phillip Lee crossed the floor while Boris Johnson was addressing Parliament on Tuesday.
He told talkRADIO he felt the party he joined in 1992 “was not the party that it had become.”