UK public sector net debt passed £3 trillion at the end of September, reaching a provisional £3,005.0 billion, as government borrowing for the month rose to £24.5 billion. The figures mark a nominal milestone, but debt was equivalent to 94.0% of gross domestic product (GDP), a smaller share than a year earlier.
The latest public-finance estimates, released on 21 October, put September borrowing £1.8 billion, or 7.7%, above September 2025. It was the second-highest September borrowing total on record, behind September 2020, without adjusting for inflation. The Office for National Statistics (ONS) said spending growth outpaced the increase in receipts.
Net debt rose by £91.7 billion over the year. The £3,005.0 billion estimate counts what the public sector owes to the UK private sector and overseas, after subtracting liquid assets. It is provisional and can change as further information arrives. The measure first passed £2 trillion in June 2020 and £1 trillion in February 2010.
Debt share falls despite higher total
The GDP comparison provides a different perspective from the headline cash total. At 94.0% of GDP, net debt was 0.7 percentage points lower than a year earlier, although the ONS said the ratio remained at levels last seen in the early 1960s. A rising nominal stock and a declining debt-to-GDP ratio can occur together because the measures compare different things: one records the amount owed, while the other relates it to the size of the economy.
A separate balance-sheet measure, public sector net financial liabilities, stood at a provisional £2,643.4 billion, or 82.7% of GDP. It includes additional financial assets and liabilities, so it is not interchangeable with net debt. The ONS estimated it was £121.7 billion higher than a year earlier and its GDP ratio had risen by 0.7 percentage points.
Borrowing and interest costs
September’s £24.5 billion deficit was £1.9 billion above the Office for Budget Responsibility’s forecast. Central government debt interest payable was £10.9 billion, up £1.6 billion, or 16.6%, on a year earlier and £2.0 billion above the forecast. The monthly figure includes the cost of servicing debt; it is not the same as the total debt stock.
Central government borrowing accounted for £21.2 billion of the September total, with local government borrowing at £2.9 billion and public corporations at £0.5 billion. Central government receipts increased by 5.2% to £90.1 billion, while current expenditure rose by 7.0% to £98.6 billion. The ONS said increases in spending were spread across public services, interest, benefits and other costs.
For the first six months of the 2026/27 financial year, borrowing was £97.8 billion. That was £4.4 billion, or 4.3%, below the same period a year earlier, but £6.0 billion above the fiscal watchdog’s forecast. The current budget deficit, which covers day-to-day public activity rather than investment, was £64.0 billion over that period, £5.7 billion lower than a year earlier but £2.4 billion above forecast.
The figures therefore give a mixed picture: the cash value of net debt crossed a significant threshold, while its share of GDP edged down year on year. Monthly borrowing and debt-interest costs were higher than a year earlier, but cumulative borrowing remained below the previous year’s level. These comparisons describe different periods and measures, rather than a single verdict on the public finances.
All September estimates remain subject to revision. The ONS noted that recent borrowing figures are particularly susceptible to change as more complete data are collected, and some public-corporation estimates are highly provisional. The £3 trillion threshold is consequently a provisional statistical estimate, not a final audited total.
