Official UK Budget forecasts were accessed almost 25,000 times before their formal release on 26 November, following a leak at the Office for Budget Responsibility (OBR), according to a report from the National Cyber Security Centre (NCSC). The documents were downloaded on at least 24,701 occasions in the hour preceding Chancellor Rachel Reeves’s speech to the House of Commons, far exceeding the 43 downloads cited in an initial internal review.
The NCSC report found that the first full download of the forecasts occurred shortly after 11.35am on Budget day, nearly an hour before the Chancellor addressed Parliament, after more than 500 failed access attempts. Once the documents were obtained, links to the files spread quickly on social media, generating tens of thousands of further downloads. Within 30 minutes, 20,547 successful downloads were recorded from more than 10,000 unique IP addresses.
The investigation also revealed that Reeves’s Spring Statement in March had been accessed 16 times before its delivery, contradicting earlier claims that the forecasts had remained secure.
The leak prompted the resignation of Richard Hughes, who stepped down as OBR chairman. The organisation described the incident as the most serious failure in its 15-year history. Analysts warned that the premature release of sensitive economic data caused significant disruption in the lead-up to the Chancellor’s address. Several Budget measures, including changes affecting middle-income homeowners and an extension of stealth tax measures, were confirmed ahead of schedule, potentially influencing market behaviour.
Kenny MacAulay, chief executive of accounting software firm Acting Office, criticised the handling of sensitive information. “It beggars belief that market-sensitive data could fall into the hands of tens of thousands of people due to sloppy document management ahead of such an important event,” he said, adding that basic compliance processes should prevent leaks of this magnitude.
Graeme Stewart, head of public sector at cybersecurity firm Check Point, highlighted the potential risks posed by the breach. “With tens of thousands able to access the full economic forecast in advance, the opportunity for market manipulation by hackers or fraudsters was immense,” he said, calling for a fundamental review of how such information is published and protected.
Hughes’s resignation followed weeks of tension between the Treasury and the OBR after the watchdog downgraded its long-term growth projections for the UK economy. Reeves later faced criticism for allegedly misleading the public on the state of public finances, after government briefings painted a bleaker picture than subsequent data suggested.
The Treasury has confirmed steps are being taken to strengthen security and protect the integrity of future economic forecasts. Going forward, OBR documents will be published exclusively through the government’s official website to prevent a repeat of the breach.
