Jackie Walker, vice-chair of the hard-left Momentum activist group, is understood to have been suspended by Labour following comments she made about Holocaust Memorial Day.
The party does not comment on individual members or their status within the party, but news of Ms Walker’s apparent removal came late on Friday evening.
It is the second time this year that the activist and ally of Jeremy Corbyn has been suspended by Labour.
It had been revealed on Thursday that she is likely to be removed from her position with Momentum at a meeting of the group’s steering committee. That session is due to take place tomorrow.