LONDON — The GMB union urged its affiliated Members of Parliament not to vote for amendments to the Representation of the People Bill that would cap political donations. Votes on the proposed amendments are scheduled for next week.

The union sent a letter to more than 80 Members of Parliament who are also members of the GMB. The proposed amendments to the Representation of the People Bill would cap political donations at either £100,000 or £1 million. The GMB union stated in the letter: "We believe this amendment risks having significant unintended consequences." The union also said: "Trade unions are already subject to a level of statutory regulation over political expenditure that no other membership organisations face." It added: "Political funds are governed by legislation, members have clear rights to opt out, and unions are subject to extensive transparency and reporting requirements." The union further stated: "Affiliation arrangements are also fundamentally different from political donations and should not be treated as though they are the same."

Labour whips have been calling Members of Parliament to urge them to heed the GMB union's warning regarding the donation cap. Some Members of Parliament have dropped their support for a donation cap following contact from Labour whips.

Stella Creasy, the Member of Parliament for Walthamstow, has introduced an amendment to cap individual political donations at £100,000. Alex Sobel has tabled an amendment that seeks to cap individual political donations at £1 million. If the Speaker selects these amendments, they will be debated on Tuesday in the House of Commons.

Creasy wrote: "Whether a million-pound individual donation from a private benefactor comes from overseas or from a UK-based billionaire, the public understand the risk remains broadly the same: that political outcomes are being sold to the highest bidder rather than being fought for through a battle of ideas." She also stated: "This Tuesday, MPs can show they have both a will and a way to protect our politics from the perception as well as the reality of impropriety."