Treasury launches Budget leak probe as MP warns of 'dead-end' inquiries

The British government has launched an official security investigation into a potential pre-Budget disclosure, prompting sharp criticism from senior lawmakers over recurring leaks that bypass Parliament.

The inquiry centres on accurate details published by Bloomberg on the morning of October 28, 2026, hours before Chancellor John Healey delivered his fiscal statement. According to Yahoo News UK reporting, the pre-Budget report revealed that the planned bank corporation tax surcharge would not return to the previous level and would consequently prove less severe than the financial sector had anticipated.

Media additions

That early revelation triggered an immediate rally in bank shares, according to coverage by Aol. In response to mounting parliamentary pressure, the Cabinet Office’s Government Security Group has stepped in to lead a formal probe, supported by the Treasury as detailed by Professional Adviser.

Permanent Secretary at the Treasury James Bowler addressed the committee in a formal letter. He stated that he had received assurances that no financial institutions, their representatives, or associated trade bodies received briefings prior to the Chancellor’s address.

However, Bowler acknowledged that on the day of the Budget, a "necessary widening of the circle of knowledge within government" takes place to prepare for delivery. He insisted that these individuals remain bound by strict confidentiality rules barring any disclosure to media outlets or financial market participants.

The response failed to satisfy the cross-party Treasury Committee. Chairwoman and Labour MP Dame Meg Hillier expressed profound scepticism regarding the utility of the newly formed probe in a letter initially sent to the Financial Conduct Authority.

"I suspect that yet another inquiry into the leak of Budget measures will turn up no evidence of a breach but plenty of reassurance that next time it will be even more secure. We cannot continue to accept this doom-loop of dead-end investigations in which everybody in the Treasury throws their hands up in despair, but nobody is ever found to have done anything wrong."

Dame Meg Hillier, Chairwoman of the Treasury Committee, via Yahoo News UK and The Independent

Hillier argued that the Treasury still needs to explain how market-sensitive information capable of moving bank share prices circulated widely in newsrooms before reaching Parliament.

The current investigation compounds security challenges for Healey, who has attempted to fortify Treasury protocols following previous leaks under successive administrations. According to Reuters reporting carried by international outlets, prior administration leak probes similarly failed to identify sources behind a Financial Times report concerning income tax plans and a Sun report detailing Bank of England bond-buying expansions.

Inquiry / Event	Reporting Outlet	Date / Timing	Outcome
Bank of England bond-buying programme	The Sun	November 2020	No source identified
Income tax plan adjustments	Financial Times	Two weeks prior to 2025 Budget	No source identified
Watchdog forecasts accessibility	Reuters	Prior administration budget	Led to tightened Treasury security under Healey
Bank corporation tax surcharge	Bloomberg	October 28, 2026	Under active investigation by Cabinet Office

What happens next

• Chancellor John Healey is scheduled to appear before the Treasury Committee on Wednesday afternoon.
• Lawmakers intend to press the Chancellor directly on the circumstances surrounding the pre-Budget bank tax disclosures during the scrutiny session.
• The Government Security Group within the Cabinet Office will continue its formal investigation into the source of the leak.