Debt and deficit
Public debt measures what the UK’s public sector owes, usually because it’s had to borrow cash to fund itself because its income has fallen short. The main measure is called ‘public sector net debt’. The Office for National Statistics and the Treasury jointly compile figures as ‘public sector finances’ and publish them every month.
More detailed figures on the nature of the public debt are published by the Debt Management Office.
The deficit measures how quickly the public sector is adding to its debt, so it amounts to total revenue minus total expenditure and investment. It’s presented as ‘public sector net borrowing’ and can also be found in the joint ONS and Treasury public sector finances.
Another measure for deficit is the public sector’s ‘current budget’, which is the same measure as for the deficit except without including investment. In other words, it’s just current income minus current spending, leaving out spending on investments for the longer term.
Deficit figures are often ‘cyclically adjusted’ because government income varies throughout the year (a year being a cycle). The government brings in more money in April, July, October and January because corporation tax receipts are assigned to these months, and income tax self-assessments affect receipts in January.
For the wider context, we have debt and deficit figures back to the Second World War thanks to the Office for Budget Responsibility.
The Institute for Fiscal Studies has also generated debt figures for the 1800s onwards.
The Office for Budget Responsibility forecasts what is expected to happen to GDP over the coming years. These figures have large margins of error for obvious reasons, and are only broadly indicative. The OBR publishes the numbers as public finance forecasts.
Meanwhile, banks and academics all produce their own estimates. Helpfully, HM Treasury collects all these forecasts in one monthly release.