This Forecast in-depth page has been updated with information available at the time of the March 2024 Economic and fiscal outlook. We are aware of a technical issue with our tableau charts across the site. Access the data from our March 2024 forecast supporting spreadsheets directly.

The Treasury manages public spending within two ‘control totals’ of about equal size:

  • departmental expenditure limits (DELs) – mostly covering spending on public services, grants and administration (collectively termed ‘resource’ spending) and investment (‘capital’ spending). These are items that can be planned over extended periods.
  • annually managed expenditure (AME) – categories of spending less amenable to multi-year planning, such as social security spending and debt interest.

The limits on departmental spending are set at Spending Reviews, when the Treasury allocates a total amount of DELs across departments and splits them into limits on resource spending (RDELs) and capital spending (CDELs). The biggest departmental budgets are those for health, education and defence. As DELs are limits rather than central targets, departments tend to spend less than the limit, so actual departmental spending is typically a little lower than the DELs themselves.

In 2024-25, we expect departmental spending to total £529.4 billion (made up of £430.2 billion of resource spending and £99.2 billion of capital spending). That would represent 43.2 per cent of all public spending and is equivalent to £18,262 per household and 19.0 per cent of national income.

  Forecast methodology

Our forecasts for departmental spending are constructed by taking the plans set out by the Treasury in Spending Reviews and applying our own forecast for how much departments will underspend relative to those plans to get to a forecast for actual spending. In years for which plans have not been set, we ask the Treasury to specify a policy assumption for the amount that it will spend. From our November 2023 forecast, we no longer assume that the Treasury will underspend against this policy assumption, which is consistent with recent historical evidence. The appropriate point to judge whether departments will underspend, and if so by how much, is when departmental allocations are set in Spending Reviews. The forecast process involves the Treasury attending challenge meetings and providing evidence on departments’ spending and their own in-year forecasts to allow the Budget Responsibility Committee to reach a judgement about underspending in the year in progress. The Treasury also provides evidence on pressures on departmental budgets in future years that informs the BRC’s judgements about underspending over the rest of the Spending Review period.

Forecast approach

The amount of departmental spending is largely at the discretion of the Treasury, so unlike most of our fiscal forecasts, our DEL spending forecasts are not produced via one or more forecasting models. Instead, the starting point is the total budget for departmental spending – and how this is split across departments – that was set at the most recent Spending Review and any subsequent changes to those plans. The latest detailed departmental plans for the years 2022-23 to 2024-25 were initially set at the 2021 Spending Review. For the years that have not yet been covered by the latest Spending Review (i.e. 2025-26 to 2028-29 in our latest forecast), the Government sets the overall current and capital DEL spending totals in each Budget or Spring Statement.

Our DEL spending forecasts are produced top-down, rather than bottom-up – for example, we do not forecast education spending by forecasting how many school pupils there will be and the average cost of teaching them. Indeed, with the exception of our in-year forecast, during which we consider Treasury information about pressures on individual departmental budgets, we typically do not look at the allocation of DELs across departments. Instead, we start with the totals for RDEL and CDEL plans, provided to us by the Treasury, and make a top-down assumption about the aggregate degree of underspending we expect against these budgets in years covered by a Spending Review. This judgement is based on historical trends, the latest in-year data and the absolute level of DEL spending. For the current year and the following year, we also consider any effects from changes in the levels of underspend carried forward from previous years, which can add to spending pressures. We also consider information from the Treasury on any additional spending pressures that may lead to claims on the Treasury’s central reserves.

In autumn forecasts, our current-year underspends forecasts are measured against initial plans for the year, as set out in Public Expenditure Statistical Analyses (PESA). (The PESA plans specify any additional spending carried forward into the current year – for example, under Budget Exchange – and also set out the Treasury’s central reserves.) In spring forecasts, these initial plans have been superseded by final plans set out in Supplementary Estimates (usually published in February). Those final plans will include underspends that are surrendered for the current year, and any allocations from the Treasury’s central reserves. At that closing stage of the year, we will also know departments’ own forecasts of spending against their final plans, which they submit to the Treasury in February. We still express underspends against the initial PESA plans, but our forecasts are now informed by the final plans and the latest news on likely underspending against those plans.

When explaining changes to our DEL forecasts, we separate them into three types to try to make it clear when the changes are the result of Government policy decisions. We distinguish between:

  • Forecast changes: this constitutes any changes to our assumptions about the degree of underspending that we expect to see against the latest departmental plans, excluding the effects of any DEL policy changes.
  • Classification changes: any statistical changes that move spending between the PSCE/PSGI elements and the non-fiscal element that does not affect the deficit, any switches between DEL and AME and new spending items included in our PSCE/PSGI DEL forecasts.
  • Policy decisions: any changes to DELs that the Government chooses to make that are not covered by either of the two categories listed above, including any changes we make to underspending assumptions in response to those policy changes. We also include Government decisions to allocate more or less DEL spending to the PSCE/PSGI elements or to other parts of DEL, since these decisions affect the deficit.

The direct contribution of departmental spending to GDP

The spending forecast is compiled both in terms of the control framework of DEL and AME, and also in terms of its economic components, such as consumption, net social benefits, current grants within the public sector, gross domestic fixed capital formation (a measure of investment) and so on. These economic splits of spending feed directly into our economy forecast, where general government consumption and investment make up around 20 per cent of GDP.

The economic splits of DEL spending are taken from OSCAR, which is the database used by the Treasury to collect financial data from across the public sector, including departments’ spending outturns and plans. The economic splits of DELs are only available on OSCAR for the years covered by DEL settlements, and departments need some time to finalise and reflect their final detailed spending plans on OSCAR after their DEL totals are set in a Spending Review. For years of the fiscal forecast where details of DEL spending are not available on OSCAR (currently 2025-26 onwards), we produce our own forecast of the economic allocation of DEL spending. Growth in spending on wages and salaries is linked to the growth in related spending areas (shown in a detailed forecast table on our website), whereas the remaining economic categories are allocated as constant shares of the remaining budget, relative to the final year for which plans exist (currently 2024-25).

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  Previous forecasts

Interpreting the pattern of revisions between previous RDEL and CDEL forecasts in difficult because of frequent classification changes that switch spending between DEL and AME. Nevertheless, some interesting trends emerge from the two charts below:

  • The RDEL chart shows spending being cut by the Coalition Government up to 2015-16, but that the RDEL totals for 2016-17 onwards implied by the Coalition’s later Budgets and Autumn Statements were raised in the 2015 Spending Review, with further increases from the 2020 Spring Budget onwards, initially relating to increases to funding for the NHS, and subsequently to Covid-related spending.
  • The CDEL chart shows little change in the profile of spending across the forecasts – with the different levels of the forecasts largely reflecting classification changes. It also shows the increase in capital spending that the present Government set out in Autumn Statement 2016 as part of its ‘National Productivity Investment Fund’.

We include tables in each EFO that show any major switches between DEL and AME, and other classification changes affecting DELs. And we publish a detailed forecast table on our website for each EFO that provides long-run consistent series for RDEL and CDEL, on the same measurement basis as the latest figures for RDEL and CDEL.

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