The Budget of His Majesty's Government is an annual budget set by HM Treasury for the following financial year, with the revenues to be gathered by HM Revenue and Customs and the expenditures of the public sector, in compliance with government policy.

For that reason, Parliament typically passed a "Vote on Account" in early spring that provided continuity of funding into the new fiscal year, up until the point that the new budget was enacted.

Since November 2017 the budget was moved to the Autumn, with a view to passing the Finance Act before the commencement of the Financial Year.

[2] Governmental departments submit their funding requests — called "Main Supply Estimates" – to HM Treasury.

The government then releases this data in a large consolidated document titled "Central Government Supply Estimates (Budget Year-Following Year): Main Supply Estimates" [4] The government reserves the right to submit "Supplementary Estimates" in the spring and winter of a given fiscal year to update its agencies' spending totals for the current financial year and report any governmental re-organizations.