Ian Murray, a long-term critic of Jeremy Corbyn’s leadership, accused him of allowing a culture of bullying to develop within Labour, but stopped short of resigning himself.
The member for Edinburgh South spoke out after seven MPs confirmed they had quit the party in protest at its poor handling of allegations of anti-Semitism and its stance on Brexit.
“We have lost the talent and expertise of seven MPs who represent everything our movement should stand for and who are personal friends,” Murray said.
“The current Labour leadership is breaking the broad church that this party once built its electoral success upon – a broad church which delivered Labour governments that lifted millions and millions of people out of poverty.
“The challenge now is for Jeremy Corbyn to listen and learn, and decide if he wants to keep the Labour Party together or if he will continue to foster a culture of bullying and intolerance where his own MPs feel unwelcome and are being forced out.
“That means listening to members who are demanding we give people the opportunity to remain in the EU in line with party policy, and learning from the distressing experiences of people like Luciana Berger so that such vile hatred and intolerance can never again be found in our movement.
“If we work together, our party can be the greatest vehicle for change in this country. It’s the only vehicle. Jeremy Corbyn must now decide if he wants to lead a party for the many or continue to restrict it to a party of the few.”
Luciana Berger, the Liverpool Wavertree MP, said she had become “embarrassed and ashamed” of representing the party, which she claimed was “institutionally anti-Semitic”.
Ms Berger was joined by fellow MPs Chris Leslie, Gavin Shuker, Mike Gapes, Ann Coffey, and Chuka Umuna to join an independent group in the House of Commons.
Mr Leslie said Labour had been “hijacked” by the far left, and claimed the party leadership had betrayed its membership by failing to back a Brexit deal that includes membership of the EU single market.