UK government borrowing costs surged to their highest level since 1998 on Tuesday, as part of a wider international sell-off in government bonds that has intensified scrutiny of Britain's fiscal position ahead of next month's budget.
Thirty-year gilt yields climbed sharply during the session, with 10-year yields also rising to around 5.2%, according to market moves cited by analysts. The increase forms part of a broader global trend affecting sovereign debt markets, driven by a combination of factors including the conflict involving Iran, which has pushed up energy costs and disrupted expectations of falling global inflation earlier in the year.
A weakening Japanese yen has removed another perceived source of financial stability, while US Treasury Secretary Scott Bessent's efforts to bring down American yields have so far failed to calm investor nerves. Analysts have also pointed to the early stages of the artificial intelligence investment boom, which has involved substantial debt issuance before the long-term returns on that capital can be properly assessed.
Against that backdrop, investors demanding higher returns to hold government debt from countries with elevated debt ratios is, in market terms, a predictable response. However, the UK entered this period of global volatility already positioned at the higher end of borrowing costs among G7 nations, a status widely linked to two decades of difficulty controlling inflation and, more recently, the country's reliance on energy imports, which stood at 43% in 2025.
Prime Minister Andy Burnham addressed the situation in a Commons speech on Tuesday, reiterating the government's commitment to Chancellor Rachel Reeves's fiscal rules. However, economists have said the speech did little to reassure bond investors about the government's approach to the UK's financial position, six weeks into Burnham's tenure alongside Chancellor John Healey.
Simon French, an economist at Panmure Liberum, said markets remained unconvinced that increased "public control" of utilities—a theme Burnham has repeatedly returned to—would translate into lower government-led inflation. "Markets are sceptical that 'devolution' and 'control' are levers for lower government-led inflation," French said. "Burnham/Healey's unenviable task is to prove they are the right levers. If they fail then a very painful period of financial repression/demand side-led disinflation will be necessary."
Jim O'Neill, the former Goldman Sachs economist, said the tone of Burnham's Commons speech was "the last thing investors wanted to hear". O'Neill, who had reportedly been considered for a role in government, told the BBC that elevated government borrowing costs would force Labour to address the triple lock on the state pension and what he described as "excessive" welfare spending. According to the analysis, there has been little indication from government so far that either policy area is being prepared for reform.
Government officials have said the forthcoming 10-year economic plan will address energy costs, defence spending, social care and housing shortages, among other priorities. However, some economists have raised the possibility that difficult fiscal decisions could be deferred in the budget, which could risk further UK-specific pressure on bond markets, particularly if disruption to global energy supplies continues through the winter months.
The rise in gilt yields comes after a period of significant political change within the governing party, with Labour having changed leadership earlier in the year before Burnham took over as prime minister. Economists have suggested that the government will need to demonstrate concrete fiscal measures in the budget to reassure bond markets, given the scale of the challenges facing the public finances.
Officials have indicated that the budget will set out a mixture of spending decisions and tax measures, though the precise balance has not yet been confirmed. Analysts tracking the bond market have said that the coming weeks, including the lead-up to the budget statement, are likely to be closely watched by investors for signs of how the government intends to manage the UK's borrowing costs relative to other G7 economies.
The Treasury has not issued a detailed response to the specific criticisms raised by economists regarding the pension triple lock or welfare spending. The situation remains subject to further developments as the government finalises its budget proposals.
