Supporters of Jeremy Corbyn and Zarah Sultana's left-wing movement, Your Party, have said a very public split between the two founders is "embarrassing" and "frustrating".
A row broke out between the former Labour leader and Ms Sultana on Thursday afternoon, after he accused her of sending out unauthorised emails encouraging paid membership.
The one-time potential prime minister accused his co-leader of wrongdoing, and said legal action was being considered, in a letter signed by four other independent MPs who were part of the founding process of Your Party.
Ms Sultana, who resigned from the Labour Party to help found the new left-wing organisation in July this year, hit back and said she had been "sidelined" by a "sexist boys club".
The 31-year-old MP added in a statement that she h