OBR forecasts are produced independently of ministers, objectively, transparently and impartially, as set out clearly by law. The spring forecast is available at: https://obr.uk/efo/economic-and-fiscal-outlook-march-2023/
For the spring forecast, the OBR have been engaged with the Treasury in the normal way and there have been regular discussions of the economic and fiscal outlook.
As set out in the Memorandum of Understanding between HM Treasury and the OBR, the forecast process involves the OBR producing multiple draft iterations of the forecasts which it shares with the Chancellor.
With regard to business rates, the 5-year forecast takes account of the Government’s £13.6 billion package of support announced at Autumn Statement 2022, and annual CPI indexation of the multiplier.
Future decisions regarding business rates will be taken in line with the normal Budget process.