Political donations in the UK have been subject to comprehensive disclosure since 2001. We study the data produced as part of this disclosure policy to evaluate the role of private and public political finance over time. Total political donations have grown by nearly 250 per cent since 2001, reaching over £100 million in real terms for the first time in 2019. This increase has been driven by donations from private individuals, who now account for approximately 60 per cent of donations in election years compared to 40–50 per cent up to the late 2010s. Furthermore, ‘super-donors’ (those contributing more than £100,000) have been a prominent driver of the rise, increasing their own share from approximately 31 per cent in 2017 to 45 per cent in 2019. We also show that private donations to the Labour Party fell sharply in the final stages of Jeremy Corbyn's leadership. These trends have benefited the Conservative Party, leading to a historic donation gap between the two main parties emerging circa 2019. We calculate that this gap between parties now stands at approximately £27 million compared to a historic average of £8–£10 million. This gap remains even after considering publicly funded ‘Short’ money provided to the opposition, which aims to increase competitive balance in the UK's democratic system.