public finances · before the Budget
Budget 2026: the numbers behind the Chancellor's choices
The Budget is on Wednesday 28 October 2026. The Chancellor starts from debt of 93.8 per cent of GDP, borrowing running £8.1 billion above the official forecast after five months, debt interest of about £109 billion a year, and a 10 year gilt yield of 5.38 per cent, against the 4.5 per cent the forecast assumed in March. This page sets out those numbers from the ONS, the Office for Budget Responsibility and the Bank of England, and what the OBR will publish on the day.
How to read this
Every figure here is official: outturn from the ONS public sector finances, forecasts from the Office for Budget Responsibility's Economic and fiscal outlook (EFO), gilt yields from the Bank of England. Forecasts are the OBR's central estimates and carry wide uncertainty. Financial years run April to March. The OBR's last forecast, in March 2026, did not assess the fiscal rules; it will do so at the Budget.
Read next: What the UK national debt is: how much the government owes and borrows, How much tax the UK government collects each year, and where it comes from and The welfare bill: what benefits actually cost
ONS Public Sector Finances, August 2026 (released 22 September 2026); OBR Public finances databank, September 2026; OBR Economic and fiscal outlook, March 2026 and November 2025; OBR Historical official forecasts database, March 2026; Bank of England series IUDMNPY to 14 October 2026; HM Treasury, Budget date letter of 31 July 2026.
The starting position
Five official numbers the Budget starts from
Each figure below is taken from the page that holds its full history and sources. Together they describe the public finances as they stand ahead of 28 October: what the state owes, what it is still borrowing, what it raises, what it spends, and the largest item of spending.
Public sector net debt was 93.8 per cent of GDP at the end of August 2026, about £2,986 billion, a level last seen in the early 1960s. Excluding the Bank of England it was about £2,870 billion.
£8.1 billion more than the OBR forecast for the same months in March. The March forecast for the whole year is £115.5 billion.
Total tax was about 36 per cent of GDP in 2025 to 2026 on the National Accounts measure, the highest share since 1951.
Total Managed Expenditure was about £1,360 billion in 2025 to 2026, on HM Treasury's PESA 2026 figures. Social protection is the largest function.
DWP's Spring Forecast 2026 figure for the year, rising to about £408.6 billion by 2030 to 2031. State Pension is the largest line.
What the debt costs
Debt interest is more than £100 billion a year
Central government spent about £108.9 billion on debt interest in 2025 to 2026, 3.5 per cent of GDP, on the OBR's measure net of the Bank of England's asset purchase facility. In 2019 to 2020 it was about £39.3 billion. After dipping to £25.2 billion in 2020 to 2021, it more than doubled in 2021 to 2022, to £55.5 billion, and doubled again in 2022 to 2023, to £111.9 billion. In the OBR's words, higher levels of debt combined with the sharp rise in interest rates since 2021 led to a significant increase in the cost of servicing it. In March the OBR forecast it rising to about £137.1 billion by 2030 to 2031. For scale, HM Treasury's PESA, which counts debt interest gross across the public sector, puts it at £130.3 billion in 2025 to 2026: more than the £125.7 billion spent on education and about twice the £65.4 billion spent on defence.
OBR Public finances databank, September 2026: outturn to 2025-26 consistent with the ONS public sector finances of 22 September 2026; 2026-27 onwards is the March 2026 EFO forecast.
Blue: outturn. Grey: OBR forecast, March 2026.
Since the forecast
Gilt yields are well above what the March forecast assumed
The OBR's March 2026 forecast was conditioned on a 10 year gilt yield of 4.5 per cent. On 14 October 2026 the Bank of England's 10 year yield was 5.38 per cent, and its average over the last 10 working days, the same kind of window the OBR uses, was 5.38 per cent, 0.9 percentage points higher. On 8 October it reached 5.43 per cent, the highest since July 2007. Gilt yields set what the government pays on new borrowing and on debt it refinances, so a rise feeds into debt interest gradually rather than at once. The October forecast will be conditioned on market rates over a window before the Budget; the OBR says it will give the timetable in the foreword of the October EFO.
Bank of England series IUDMNPY, 10 year nominal par yield, mean of daily values by year, then by month; the latest month is to 14 October. The OBR March 2026 assumption (4.5 per cent) is from EFO Table 2.1.
Room against the rules
The last official headroom was £22 billion
The government's main fiscal rule requires the current budget, day to day spending against receipts, to be in surplus in 2029 to 2030, which at this Budget becomes the third year of the forecast. At the November 2025 Budget the OBR judged the rule met by a margin of £22 billion, 0.6 per cent of GDP, and put the probability of meeting it at 59 per cent. The March 2026 forecast did not assess the rules, so that is the latest official headroom, though its central forecast showed a current surplus of £24 billion in 2029 to 2030. The OBR's own sensitivities show how quickly a margin of that size can move.
- A sustained 1 percentage point rise in Bank Rate and gilt yields would raise borrowing by £15 billion in 2030 to 2031, on the OBR's March 2026 estimate; a fall would lower it by a similar amount.
- On the OBR's debt interest ready reckoner, a 1 point rise in gilt rates alone adds £8.4 billion to debt interest in 2029 to 2030 and £10.4 billion in 2030 to 2031. A 1 point rise in inflation adds £9.6 billion in 2029 to 2030, through index linked gilts.
- These are the OBR's rules of thumb for a single change with everything else held still. The assessment that counts is the one the OBR publishes on 28 October, which will also reflect growth, receipts, spending and any Budget measures.
Forecast and outturn
How the forecast for last year's borrowing moved
Borrowing in 2025 to 2026 came in at about £134.3 billion. In March 2024 the official forecast for that year was £77.5 billion; it was raised at each of the next three forecasts, to £138.3 billion in November 2025, and trimmed to £132.7 billion in March 2026. It had held at about £77 billion in every forecast from November 2022 to March 2024. Not all of the change is forecasting error: forecasts also move when governments change policy. For this year, borrowing to August is £8.1 billion above the March forecast for those months.
Forecasts: OBR Historical official forecasts database, March 2026 (sheet £PSNB). Outturn: OBR Public finances databank September 2026, matching the sum of ONS monthly borrowing (J5II) for April 2025 to March 2026. Outturn is still subject to revision.
Grey: official forecasts for 2025 to 2026, by date made. Blue: outturn.
On the day
What to look for on 28 October
The OBR publishes its Economic and fiscal outlook on Budget day. This page will add a Budget day section from those documents, comparing the March and October forecasts line by line.
- Headroom against the current budget rule in 2029 to 2030, and the OBR's probability of meeting it, against £22 billion and 59 per cent in November 2025.
- Borrowing forecasts for 2026 to 2027 onwards, against £115.5 billion for this year in March.
- The debt interest forecast, against £137.1 billion for 2030 to 2031 in March, and the gilt yields it is conditioned on.
- Total tax as a share of GDP, against a forecast peak of 38.5 per cent in 2030 to 2031 in March (36 per cent in 2025 to 2026).
- The OBR's costing of each Budget measure, the policy table that shows what each one raises or costs a year.
- The welfare forecast, which DWP republishes in its outturn and forecast tables.
Questions this raises
Questions ahead of the Budget
- When is the 2026 Budget?
- Wednesday 28 October 2026. HM Treasury confirmed the date in the Chancellor's letter to the Treasury Committee of 31 July 2026, and the OBR publishes its forecast the same day.
- How much does the UK spend on debt interest?
- Central government spent about £108.9 billion in 2025 to 2026, 3.5 per cent of GDP, on the OBR's measure net of the Bank of England's asset purchase facility. The March 2026 forecast had it rising to about £137.1 billion by 2030 to 2031.
- What is fiscal headroom?
- The margin by which the government is forecast to meet its main fiscal rule, a current budget surplus in 2029 to 2030. The OBR put it at £22 billion in November 2025; it will publish a new figure on 28 October.
- Why do gilt yields matter for the Budget?
- They set the cost of new government borrowing and of refinancing old debt. The March forecast assumed a 10 year yield of 4.5 per cent, a 10 working day average; the same average to 14 October was 5.38 per cent. On the OBR's estimate a sustained 1 point rise in Bank Rate and gilt yields adds about £15 billion to borrowing in 2030 to 2031.
Sources & method
Data provenance
- Public sector finances, UK: August 2026, ONS ↗· Open Government Licence v3.0
- Economic and fiscal outlook, March 2026, and detailed forecast tables (debt interest ready reckoner), OBR ↗· Open Government Licence v3.0
- Economic and fiscal outlook, November 2025, OBR ↗· Open Government Licence v3.0
- Public finances databank, September 2026, and Historical official forecasts database, March 2026, OBR ↗· Open Government Licence v3.0
- 10 year nominal par gilt yield, series IUDMNPY, Bank of England ↗· Bank of England terms of use
- October 2026 forecast timetable, OBR, 10 September 2026 ↗· Open Government Licence v3.0
- Chancellor letter to the Treasury Select Committee: Budget 2026 date, HM Treasury ↗· Open Government Licence v3.0
- Public Expenditure Statistical Analyses 2026 (defence and education by function), HM Treasury ↗· Open Government Licence v3.0
Caveats & data notes
- Forecasts are the OBR's central estimates. Its March 2026 simulations put a 60 per cent chance on borrowing in 2030 to 2031 falling anywhere between a surplus of £43 billion and a deficit of £152 billion.
- Debt interest in the chart is central government's, net of the Bank of England's asset purchase facility, the OBR's headline measure. The comparison with education and defence uses HM Treasury's PESA, which counts gross public sector debt interest (£130.3 billion in 2025 to 2026), so that all three figures are on the same basis.
- The headroom figure of £22 billion is from November 2025. The OBR did not assess the fiscal rules in March 2026, so there is no more recent official figure until 28 October.
- The OBR's sensitivities change one thing at a time. They are not a forecast of the October numbers.
- Differences between successive borrowing forecasts include the effect of policy decisions, not only forecasting error.
- The OBR's 4.5 per cent assumption is an average over the 10 working days to 22 January 2026. The page compares it with the same kind of 10 day average, and with single days only for the latest and peak readings.
- The total tax figure (36 per cent) is the OBR National Accounts measure; the spending figure (44.3 per cent) is from HM Treasury PESA 2026, which can differ slightly from the OBR databank (44.5 per cent for 2025 to 2026).
- Outturn for 2025 to 2026 is still provisional and will be revised by the ONS.
Every figure on this page traces to its official source. Share it as it stands.
Keep going
Related deep dives
UK public sector net debt is about 94 per cent of GDP, roughly 2,986 billion pounds at the end of August 2026 (2,870 billion excluding the Bank of England): what the government owes and borrows, this year's deficit, and the fuller balance sheet of net worth and net financial liabilities.
The UK government collected about 939 billion pounds in taxes and National Insurance through HMRC in 2025-26, four taxes raise about 86 per cent of it, and the whole tax take is now about 36 per cent of GDP, the highest share since 1951.
UK welfare spending at about 333.8 billion pounds in 2025-26, heading to 408.6 billion by 2030-31 on DWP forecasts, the State Pension the biggest line and disability benefits the fastest growing at 44 per cent.
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