An eighth Labour Member of Parliament quit the party on Wednesday in protest against leader Jeremy Corbyn, joining a mounting rebellion sparked by rows over anti-Semitism and Brexit.
Joan Ryan told BBC radio that Corbyn had “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 said.
Seven MPs broke with the opposition party on Monday in the biggest split in British politics since 1981.
They will sit as an independent group in parliament for now and have announced plans for a new centrist party.
Ryan said there was a “large number” of Labour MPs who were unhappy with the leadership and that she hoped other party members would join the new Independent Group.
The Sun and ITV reported that up to three Conservative MPs are considering joining the group in what would be a radical shift in Britain's political landscape.
Britain's two main parties are badly divided over Brexit and the tensions have come to a head as the March 29 deadline for the country's departure from the bloc looms.
Labour has also been plagued by claims of anti-Semitism ever since Corbyn, a lifelong eurosceptic and supporter of anti-Israel groups, became its leader in 2015.