Labour affiliated trade unions GMB and Unite have donated more than £3.9m ($5.5m) to the party since the general election, according to official data. The figures, taken from the Electoral Commission and assembled by IBTimes UK, relate to the central party, local Labour parties (CLPs) and Labour MPs.
The data includes cash and non-cash donations, such as administration services and premises, and comes after Jeremy Corbyn reignited Labour's internal row over the party's position on the Trident nuclear deterrent when he appeared on the BBC's Andrew Marr show on 17 January.
The Campaign for Nuclear Disarmament (CND) vice-president suggested that the UK should keep the system's Vanguard-class submarine fleet but scrap their nuclear payload.
The comments came after reports claimed Unite's general secretary Len McCluskey is set to "warn" the Labour leader over the issue. And the GMB, which also represents submarine workers, will oppose Corbyn's policy to not renew Trident.
"It is understood that senior figures in the GMB union believe the plan is 'incoherent' and 'not credible' and that the organisation will not endorse Corbyn's idea," the Daily Telegraph reported.
Shadow defence secretary Emily Thornberry, a unilateralist, will be leading Labour's defence policy review after replacing Angela Eagle. The consultation will call on Labour members, affiliates and the wider public to contribute to its work. Crucially, the review will look at the party's policy on Trident and is expected to report in June.
"We will encourage the widest possible participation of Labour party members and affiliates, as well as defence specialists, NGOs and the armed forces. At every stage of the process, we will give full scope to the wide range of views on this subject in an atmosphere of mutual respect and trust," Thornberry said.