Chancellor John Healey is reportedly weighing a windfall tax on banks and oil companies for his late-October budget, the first under Prime Minister Andy Burnham, as he looks for ways to fund support for households facing rising energy bills. Britain's four biggest lenders – HSBC, NatWest, Barclays and Lloyds Banking Group – have made £200bn in pre-tax profits over the past five years, largely thanks to higher interest rates, drawing criticism from campaigners including the TUC and Positive Money, who argue the windfall should be taxed to help offset the cost of living.

Any UK levy would follow similar moves across Europe. Spain introduced a 4.8% "solidarity tax" on banks' domestic revenue in 2022, later extended to 2027 with rates of 1-7%, raising €1.3bn and €1.7bn in its first two years despite legal challenges and warnings from the ECB and IMF. Lithuania imposed a 60% tax in 2023 on banks' excess net interest income to fund infrastructure and defence spending, after lenders' profits were forecast to triple amid rising rates following Russia's invasion of Ukraine.