Britain’s Government Security Group has opened an investigation into a possible leak of market-sensitive Budget measures, after details of a bank tax rise appeared in the media hours before Chancellor John Healey delivered his Budget on 28 October.
The inquiry was confirmed in a letter from Treasury permanent secretary James Bowler to the Treasury Committee, published on Tuesday. Bowler said the Cabinet Office’s security unit was leading the investigation, with the Treasury supporting its work.
The concern centres on a Bloomberg report published at about 10.45am on Budget day, almost two hours before Healey spoke, which said the bank corporation tax surcharge would stay below the 8 per cent level lenders had feared and that any increase would be temporary. Bank shares rallied after the report. Healey later announced the surcharge would rise from 3 per cent to 6 per cent for 15 months from 1 January 2027.
Bowler told the committee he had been assured that no banks, their representatives or trade bodies were briefed on the changes before the statement. Committee chair Dame Meg Hillier said she suspected the inquiry would find no evidence of a breach, but that she would press Healey for answers when he appears before the committee on Wednesday.
The Financial Conduct Authority said on 3 November it would work with the Treasury and the Cabinet Office and consider the evidence to decide whether action under market abuse rules was appropriate. The regulator said the Treasury and Cabinet Office were best placed to determine whether any unlawful disclosure of inside information had occurred.
The inquiry is a setback for Healey, who has sought to tighten Treasury security since last year’s Budget, when the Office for Budget Responsibility’s forecasts were accessible before then-Chancellor Rachel Reeves began speaking. Confirmation of an investigation does not establish that an unlawful disclosure occurred or that anyone traded improperly.
Sources: Reuters, “UK launches investigation into budget leak” (https://www.reuters.com/world/uk/uk-launches-investigation-into-budget-leak-2026-11-10/); Professional Adviser, “Treasury confirms investigation into potential Budget leak” (https://www.professionaladviser.com/news/4538717/treasury-confirms-investigation-potential-budget-leak); SRN News, “UK launches investigation into bank tax budget leak” (https://srnnews.com/uk-launches-investigation-into-budget-leak/).
