The briefing, Taking Big Money Out of Politics, reveals that the share of private political donations coming from individuals and companies giving £1 million or more has surged from just 1 per cent in 2015 to over a third (35 per cent) in 2024 – a 35-fold increase in under a decade.

The findings come as election spending has hit a record high with parties and candidates spending over £90 million at the 2024 general election, the most in modern UK history, and nearly 80 per cent more than was spent in 2015.

The anti-corruption organisation warns that at this rate, over half of all political contributions could soon come from around a dozen individuals – accounting for less than 0.00002 per cent of eligible voters.

“A decade ago, million-pound donations accounted for just a penny in every pound given to political parties. Today, they account for more than a third. That is not a gradual trend – it is a dramatic takeover of political funding by a tiny number of ultra-wealthy individuals,” said Duncan Hames, Director of Policy, Transparency International UK.

The briefing highlights the scale of the problem with a striking comparison, where the largest single political contribution from a living donor – Chris Harborne’s £9 million gift to Reform UK in 2025 – would take the average person around 3,000 years to match, even if they donated all of their savings.  

The growing dependency of political parties on a shrinking pool of wealthy benefactors is increasing the risk of corruption, undue influence and foreign interference in UK politics. “Successive governments have left campaign finance reform to languish in the long grass, but it is clear that big money is corrupting our politics. It is time for a meaningful cap on donations,” Hames explained.

While the Representation of the People Bill includes welcome measures to tackle foreign interference through shell companies and unincorporated associations, Transparency International UK warns that without a cap on individual donations and a reduction in campaign spending limits, the legislation will fail to address the core driver of declining public trust in politics.

Polling shows 84 per cent of the public believe wealthy individuals use donations to advance their own interests, and two-thirds support a cap of £50,000 or less.

“The elections bill is an opportunity for MPs to show they are serious about earning back the public’s trust. They should take that opportunity to cap donations, to protect our democracy from being bought by the highest bidders,” concluded Hames.