Labour Lords are planning a vote of no confidence in Jeremy Corbyn over antisemitism in the Labour Party.
The peers are due to hold an emergency meeting on Monday to discuss the idea, with the potential vote held over Tuesday and Wednesday.
It the vote is passed it would have no formal effect but would be a major blow to the authority of the Labour leader.
A Labour source told the Guardian it would be “both undemocratic and absurd for unelected peers with no mandate to seek to remove an elected leader who twice won the landslide support of Labour’s membership and led Labour to the biggest increase in the party’s vote since 1945”.
Mr Corbyn is to hold his own emergency meeting of his shadow cabinet on Monday to discuss the Jew-hate crisis – amid rising concerns about the impact of the row on Labour's own staff.
It will be the first time the Labour leader has agreed to discuss the issue of antisemitism with his senior MPs.
Today, party staff represented by the GMB trade union voted 124 to four for a motion that demanded the party apologise and affirmed support for whisteblowers, after Labour hit out at "disaffected" ex-staffers who spoke to journalists about the crisis.