Joan Ryan, the MP for Enfield North in London, became the eighth Labour MP to quit the party in protest against leader Jeremy Corbyn and his handling of Brexit and anti-Semitism allegations.
"He has introduced or allowed to happen in our party this scourge of anti-Semitism. It has completely infected the party. The other huge problem is that I think Jeremy Corbyn is aiding and abetting a hard Brexit," she told the BBC in an interview on Wednesday, 20 February.
In an interview on LBC radio she said anyone who disagreed with Corbyn was targeted, which made the party feel like a "cult".
It is the biggest split in British politics since 1981, when moderate MPs broke away from the Labour Party and formed the SDP, which later merged with the Liberals.
There are strong rumours the Independent Group, which was launched on Monday, 18 February, by Chuka Umunna and six other defectors, would be joined by two or three Conservative MPs.
Soubry, Heidi Allen and Sarah Wollaston — all Remainers who have urged Theresa May to rule out a no-deal Brexit — are said to be considering their positions.
They will sit as an independent group in parliament for now and have announced plans for a new centrist party.
Ryan, 63, is a backbencher whose only previous claim to fame was in 2009 when the Daily Telegraph exposed her expenses. She lost her seat the following year but was surprisingly reselected by the Labour Party and won it back in 2015.
She said she believed more Labour MPs would defect but there has been a furious reaction among grassroots Labour Party members who have urged Ryan and the other seven to resign and fight by-elections to test the popularity of their views with voters.
Britain's two main parties are both split down the middle on the issue of Brexit as the UK hurtles towards the March 29 without a deal in place.
Labour has been plagued by claims of anti-Semitism ever since Corbyn, a lifelong supporter of the Palestinian cause, became its leader in 2015.Corbyn supporters say critics are conflating anti-Semitism with opposition to the policies of the Israeli state.