Zarah Sultana has boycotted day one of the Your Party Conference over the expulsion of members of left-wing groups.
Ms Sultana co-founded Your Party with Jeremy Corbyn in July, but the new movement has been marred with infighting from the outset.
There was a row on the eve of conference after it emerged members of the Socialist Workers Party (SWP) had been expelled from Your Party, as its rules do not permit dual membership.
Going to be hard for Your Party to recover from this. It’s either a popular front which means an activist alliance of left parties and greens - or an actual small parliamentary-orientated party. At this point in the game Sultana is probably right in principle but woefully wrong in tactics.