The Office for National Statistics published Public sector finances, UK: September 2026 on 21 October 2026. The headline: public sector net debt was provisionally £3,005.0 billion at the end of September, above £3 trillion for the first time. Net debt first passed £1 trillion in February 2010 and £2 trillion in June 2020.

As a share of the economy, the picture is different. Net debt was 94.0% of GDP, 0.7 percentage points lower than a year earlier and 1.2 points below the Office for Budget Responsibility (OBR) forecast, because nominal GDP grew faster than debt. The ONS says that is still a level “last seen in the early 1960s.”

£10.9 billion went on central government debt interest in September alone, the highest September since monthly records began in 1997.

September borrowing

  • Public sector net borrowing: £24.5 billion, up £1.8 billion (7.7%) on September 2025 and £1.9 billion above the OBR forecast. It was the second-highest September on record, after 2020 (not adjusted for inflation).
  • Central government debt interest payable: £10.9 billion, up £1.6 billion (16.6%). £4.0 billion of that was the capital uplift on index-linked gilts, driven by a 0.6% rise in the Retail Prices Index between June and July.
  • Receipts rose 5.2% to £90.1 billion. Current spending rose 7.0% to £98.6 billion, with increases in benefits, public services, interest and transfers to councils.
  • The September figure includes £1.9 billion accrued for this winter’s Winter Fuel Payments.

The year so far (April to September)

  • Borrowing: £97.8 billion. That is £4.4 billion less than a year earlier but £6.0 billion above the OBR forecast. It equals 3.1% of GDP, the 10th-highest April-to-September figure since 1993.
  • Receipts ran £5.8 billion ahead of forecast, led by Corporation Tax. Spending ran £8.9 billion ahead, including debt interest £3.8 billion higher and benefits, including pensions, £2.5 billion higher.
  • Current budget deficit (day-to-day borrowing): £64.0 billion, £2.4 billion above forecast.

The fiscal rules

The government’s rules aim for a current-budget surplus and for public sector net financial liabilities (PSNFL) to fall as a share of GDP by the financial year ending March 2030. The ONS reports PSNFL at 82.7% of GDP at the end of September, 0.7 points higher than a year earlier. The current budget deficit was £47.3 billion in 2025-26. The government has confirmed the Budget for 28 October 2026, with a new OBR forecast. The next ONS release is 20 November.

Citizen impact: The UK spent £10.9 billion on central government debt interest in one month, more than the £8.8 billion of central government net investment that month. Index-linked gilts mean higher RPI inflation feeds straight into the interest bill: £4.0 billion of September’s total. Who pays: taxpayers, now and in the Budget a week from now, which starts £6 billion behind forecast on borrowing for the year to date. Who gains: holders of index-linked gilts, whose payouts rise with RPI.

What this piece refuses

Do not write that debt is “out of control” relative to the economy. The ONS reports the debt-to-GDP ratio fell by 0.7 points over the year. The £3 trillion milestone is in cash terms and provisional. Do not call this a “borrowing crisis deepening”. Year-to-date borrowing is £4.4 billion lower than last year, though above forecast. Do not predict Budget tax rises from this release. The ONS does not forecast policy.

Bottom line

Verified from the ONS bulletin of 21 October 2026: net debt £3,005.0 billion (94.0% of GDP), the first time above £3 trillion in cash terms but lower as a share of GDP than a year ago. September borrowing was £24.5 billion (+£1.9 billion versus forecast), debt interest £10.9 billion, and year-to-date borrowing £97.8 billion (+£6.0 billion versus forecast). Budget: 28 October.