Philip Hammond's first and final Spring Budget will take place against a backdrop of intense – if unofficial – posturing and jostling for position ahead of formal negotiations.
The Budget will be watched closely for any update on the government's goals in negotiations if official forecasts of the effect of Brexit on the UK economy change. The previous calculations from the Office for Budget Responsibility showed a £60bn effect on UK GDP over the next Parliament.
After notification of the intent to leave has been given to the EU the UK will leave within two years.
The March Budget will be the last to take place in the Spring, as the chancellor moves to a timetable of one Budget per year, replacing the Autumn Statement – although at the price of having three budgetary statements within one year.
The UK's two fiscal statements per year had been seen as unusual internationally. The International Monetary Fund had previously been critical of the "frequency with which fiscal policy objectives appear to change, combined with the Autumn Statement effectively evolving, in recent years, into a mini budget."
The Autumn Budget will be complemented by a Spring Statement of the fiscal position of the UK government in order to comply with requirements for the Office for Budget Responsibility to be able to analyse public finances twice per year.
The Treasury's announcement said: "This will be the last Budget to take place in the Spring. As announced at the Autumn Statement, following the Spring Budget, Budgets will be delivered in the Autumn."