Unite the Union

Unite the Union — Labour's Largest Union Funder 
 Full name: Unite the Union
 Approx total donated (2024-2026): £3-5 million (via affiliation fees, direct donations, and campaign support)
 Type: Trade union — Labour's largest union affiliate
 Why they donate: Represents working-class interests across manufacturing, transport, public services, and logistics. Seeks to influence Labour's industrial relations, workers' rights, and nationalisation policy.
 Controversies: Internal factional battles within Labour have been heavily influenced by Unite. Accusations of "block vote" influence over candidate selection and policy direction. Under previous leader Len McCluskey, Unite was a major force in Labour's leftward shift. Current leadership under Sharon Graham has been more focused on industrial action but remains influential. 
 Notes 
 
 Around 1.2 million members 
 Also funds Labour MPs directly through constituency donations 
 Was central to the factional battles of the Corbyn era 
 Sharon Graham's leadership has deprioritised internal Labour politics relative to industrial strategy