Keir Starmer suffered a blow today as Andy McDonald quit his shadow cabinet complaining that the leader would not back a £15 an hour minimum wage.
The shadow employment minister said his position had been made 'untenable' by Sir Keir's refusal to support the dramatic hike.
He said he had been ordered to go into a meeting yesterday arguing that the party could not endorse the higher minimum wage and statutory sick pay.
Mr McDonald was seen as a close ally of Jeremy Corbyn, and his departure comes amid growing anger on the Left of the party.
Sir Keir has pushed through rules making it harder for Corbynite activists to trigger deselection votes for MPs, and raising the number of nominations that a left-winger would need to stand for the leadership in future.
And McDonald said his position had been made 'untenable' by Sir Keir's refusal to support the dramatic hike.
Mr McDonald wrote: 'Yesterday your office instructed me to go into a meeting to argue against a national minimum wage of £15 per hour and against statutory sick pay at the living wage. This is something I could not do.
'After many months of a pandemic when we made commitments to stand by key workers I cannot now look those same workers in the eye and tell them they are not worth a wage that is enough to live on, or that they don't deserve security when they are ill.'
He added: 'I joined your front bench team on the basis of the pledges that you made in the leadership campaign to bring about unity within the party and maintain our commitment to socialist policies.
'After 18 months of your leadership our movement is more divided than ever and the pledges you made to the membership are not being honoured. This is just the latest of many.'
The resignation is a blow for Sir Keir (pictured at conference today) as he tries to show he has a grip on the Labour Party