Worse-than-expected public spending data has piled pressure on Rachel Reeves in the run-up to next week’s spring statement, with UK government borrowing rising by much more than expected last month to £10.7bn.

In a setback for the chancellor, the monthly total – the difference between total public sector spending and income – sharply overshot a Reuters poll of experts that had predicted a deficit of £6.6bn.

The figures from the Office for National Statistics, published before next week’s crunch statement, showed February’s borrowing was little changed from the same month a year earlier, but over the financial year to date it was up almost £15bn on the same period last year.

Isabel Stockton, a senior research economist at the Institute for Fiscal Studies, said a simple extrapolation suggested borrowing for the financial year as a whole could now come in at about £151bn – as much as £23bn more than forecast by the independent Office for Budget Responsibility (OBR) in October.

“Having boxed herself in with promises to meet her fiscal targets, not to raise taxes further and not to return to austerity for public services, easy or risk-free options for the chancellor are in short supply,” she said.

Reeves is expected to announce spending cuts at Wednesday’s spring statement, which comes against a backdrop of sluggish economic growth, stubbornly high inflation and rising government borrowing costs.

Updated forecasts from the OBR are expected to show her self-imposed fiscal rules would be broken without action; giving Labour ammunition to justify welfare cuts announced earlier this week.

At last October’s budget the chancellor had left £9.9bn against her main fiscal target, which requires day-to-day spending to be matched by revenues. However, borrowing costs have risen sharply on global markets, fuelling a higher debt interest bill. Alongside a weak growth outlook, economists warn this will have wiped out the chancellor’s headroom.

The latest snapshot of the public finances comes after the OBR has finalised its forecasts for the spring statement, which were due to be handed to the Treasury on Friday, and underscores the challenge facing the chancellor. The forecast is poised to halve the UK’s expected growth rate for the 2025 financial year from 2% to about 1%, according to a Telegraph report.

James Smith, a research director at the Resolution Foundation thinktank, said the figures highlighted the “perilous state” of the public finances. “The chancellor is reportedly ruling out tax rises to meet these rules and is set to cut spending on benefits and public services instead. But, if the economy doesn’t turn a corner soon, tax rises will need to come back into play.”

The February figures show the government borrowed £132bn in the first 11 months of the financial year 2024-25, almost £15bn more than at the same point in the last financial year and the third highest financial year-to-February borrowing since monthly records began in 1993.

Reeves has said her fiscal rules are “non-negotiable”, aiming to draw a political line with Liz Truss, and has also ruled out raising taxes, leaving spending cuts and a drive to find efficiency savings as the path of least resistance.

However, the strategy is rattling backbench Labour MPs and risks hitting the government’s other promises to grow the economy, avoid a return to austerity and fix battered public services.

Highlighting a growing backlash against the chancellor, a group of Britain’s most distinguished economists wrote in a letter to the Financial Times on Friday saying it would be a “profound mistake” to cut spending or investment.

The economists – including the professors Jonathan Portes from King’s College London, Mariana Mazzucato from University College London, Ha-Joon Chang from Soas University of London, and David Vines from the University of Oxford – argued that “the last 15 years have taught us that the UK cannot cut its way to growth”.

Darren Jones, the chief secretary to the Treasury, said the government needed to go “further and faster to create an agile and productive state that works for people”.

He said: “At the core of this urgent mission is sound public finances, based on our non-negotiable fiscal rules. This government will never play fast and loose with the public finances.”