This was despite calls from party staff for the investigation to be moved on to the next disciplinary stage.

Mr Corbyn found himself under mounting pressure to sack Mr Williamson after Jon Lansman, the founder of the grassroots Momentum group and key Corbyn-ally also said the MP ‘has to go’.

Mr Lansman accused Mr Williamson of showing ‘contempt’ for the panel’s ruling by tweeting that he had received an ‘avalanche’ of support from grassroots members.

The decision to let Mr Williamson back into the party was met with condemnation from many MPs on both sides of the house and many Jewish community figures.

More than 60 MPs have signed a motion calling for a Parliamentary Labour Party (PLP) vote on withdrawing the whip from Mr Williamson for 12 months for bringing the party into disrepute.

The motion calls for the case to be referred to the parliamentary committee – the influential backbench body which meets weekly with Mr Corbyn – at its next meeting on Wednesday.

If approved, it would then go to a full PLP vote at Westminster.

The motion says: ‘Due to the exceptional circumstances in this case we are of the view that the allegation of bringing the Labour Party into disrepute made against Chris Williamson warrants an investigation by the parliamentary committee under this standing order and full consideration given to a recommendation of removal of the whip to the PLP.

‘We therefore seek to ask the PLP to take action to suspend the whip from Chris Williamson for a period of a year.’

MPs who signed the motion include Yvette Cooper, Dame Margaret Hodge, Wes Streeting, David Lammy and Diana Johnson.

The latest move to have him suspended from the PLP came after Mr Corbyn ignored calls, led by deputy leader Tom Watson, to step in and withdraw the whip himself.

A Labour source insisted Mr Corbyn was not involved in the party’s disciplinary processes or individual cases.