Britain has a new deficit forecast. The IMF's later figure was usually higher.
On 28 October the UK's official forecaster put government borrowing this year at 4.2% of GDP. The IMF gives its first figure for 2026 in April.
What happened
The Office for Budget Responsibility said government borrowing will be 4.2% of GDP this year and 3.4% next year, as John Healey gave his first Budget.
UK government borrowing will be 4.2% of GDP this year, the Office for Budget Responsibility (OBR) says. The government’s independent forecaster gave the figure on , the day Chancellor John Healey presented his first Budget. Borrowing is the gap between what the state spends and what it takes in. The forecaster expects 3.4% next year and 1.8% by 2030-31.
Healey said the state will spend £14bn more on interest on its debt this year, because the war in Iran has pushed up borrowing costs for governments around the world. He left £15bn of room against his main rule on day-to-day spending, down from £23.6bn left by Rachel Reeves in the spring. The forecaster says borrowing next year could be £17bn higher if energy prices rise further and stay high, or £12bn lower if they fall.
The International Monetary Fund (IMF) counts the UK deficit in its own way. It uses the calendar year, January to December, while the OBR uses the financial year that starts in April. It also uses a measure called general government borrowing. On that measure the Budget papers put 2026-27 at 4.5% of GDP. The IMF’s own table, updated on before the Budget, puts 2026 at 3.8%.
General government net lending/borrowing. Net lending (+)/ borrowing (–) is calculated as revenue minus total expenditure.
IMF DataMapper, World Economic Outlook indicators
The IMF gives its first figure for the whole of 2026 in its World Economic Outlook and has not yet named the date. In 2019 the April report came out on , and in 2025 on . Before then the Office for National Statistics (ONS) gives monthly figures, and the figure for December, the last month of 2026, comes on .
Sources: theguardian.com
The Pattern
We looked for cases where the Office for Budget Responsibility gave its borrowing forecast for the current year on a Budget day in the autumn, and the IMF later gave its first figure for that whole year in April. We found five such Budgets, from 2017 to 2025. Before 2017 the autumn forecast came with a smaller Autumn Statement. Four times the IMF’s first figure showed a bigger deficit than the forecast.
Show the other 3 cases
The Read
From April to the UK borrowed £97.8bn, or 3.1% of GDP. That is 0.3 points less than a year earlier, but £6.0bn more than the forecaster expected. In September alone the state borrowed £24.5bn, £1.8bn more than in , partly because interest on the debt rose. For 2025 the IMF’s first figure was 5.4%, so a year a little lower than 2025 still points above 4.2%. The Budget papers point the same way, with 4.5% on the measure the IMF uses.
There are reasons for doubt. All five times it was the same forecaster and the same IMF, and all five Budgets came after 2017. The two biggest gaps came in the two most recent years, 1.2 points in 2024 and 0.9 points in 2025. In the other three years the IMF figure landed within 0.2 points of the forecast, which this year means 4.0% to 4.4%. The IMF’s own table, made before the Budget, says 3.8%, and a figure that low would take the deficit below the forecast for the first time since 2017.
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