Labour will try to change political donation laws after Reform received a bumper £72million from two businessmen in as many days.

Left-wing MPs are pushing for a £100,000 cap that will apply to expats donating to UK parties but not to trade unions, which have given tens of millions of pounds to Labour over the past decade, or UK-based donors.

The planned changes would be retrospective, Local Government Secretary Angela Rayner confirmed, sparking fury from rivals.

In July, Ms Rayner herself received around £30,000 in donations, with similar sums paid earlier this year. Her donors would be unaffected by the cap she is backing.

The Ashton-under-Lyne MP previously made headlines after quitting as Deputy Prime Minister under Sir Keir Starmer amid a scandal around her underpayment of stamp duty on a £800,000 seafront property in Brighton.

Andy Burnham reappointed her back to the job when he became Prime Minister earlier this year.

Speaking to Sky News on Monday, Ms Rayner said the law would “be backdated” and will apply to “overseas donors” and those who have “recently returned to the UK”.

She added: “Look, we’re saying that if you don’t pay taxes, if you don’t live here, you can’t buy your way into our democracy.”

Asked on the BBC‘s Sunday With Laura Kuenssberg if Nigel Farage might need to hand back the money given to him by cryptocurrency billionaires Ben Delo and Christopher Harborne, Ms Rayner said she did not know their “individual circumstances”.

But she added: “With the retrospective action, anyone that’s received donations that don’t comply with what was in the Rycroft review, what legislation is currently going through Parliament, would have 60 days to return that money.”

Reform UK said it was “100% confident” that both are legal and “won’t ever have to be handed back”.

Senior Reform figures slammed Labour over the plans, with Westminster insiders pointing out that Labour pocketed £4million from Quadrature Capital in 2024, which has funds based in the Cayman Islands.

Treasury spokesman Robert Jenrick wrote: “They’re behaving like gangsters. We have to stop their shoddy stitch-up.”

Labour is also said to be plotting a cap on donations from any individual, but not trade unions. Mr Burnham previously backed a cap of £500,000, but is believed to have stopped backing it after lobbying by trade union barons.

Home affairs spokesman Zia Yusuf said the pledge to backdate the terms of the Bill would “weaponise Parliament” to “confiscate donations”.

He dubbed it “literally changing the rules after the fact to hurt and punish a political opponent”, adding: “There is no precedent for this in modern British political history. How can anybody operate on these terms?”