Currently Labour’s biggest union donor, Unite general secretary, Sharon Graham, told the Guardian that they would continue to £1 million in affiliation fees to the party.
In an interview with the publication, Ms Graham said that “there’s a lot of other money that we use from our political fund where, actually, I’m not sure we’re getting the best value for it”.
When she took on the role after replacing Len McCluskey in August, Ms Graham promised to “completely refocus” the union.
“I will be a general secretary for the workers, for my members,” she said at the time.
It comes after she refused to attend Labour’s annual conference in Brighton this year as she said current industrial disputes would have to take priority.
The latest move threatens to deepen the divide between Unite and Labour leader Sir Keir Starmer, despite a Labour source saying “Relationships with the unions are good.”
They added: “Unions have always funded campaigns and causes for their memberships.”
Ms Graham told the Guardian: “The fact that I am being quite robust is because Labour needs to talk about workers, needs to defend workers and needs to defend communities.”
She told the newspaper that money would instead be funnelled into projects which would “set the pace” for Labour to follow.
She did not reveal how much funding would be cut by.