The 2009 United Kingdom Budget, officially known as Budget 2009: Building Britain's Future, was formally delivered by Alistair Darling in the House of Commons on 22 April 2009.^[1] It introduced new tax, spending and debt rises in a financial environment of rising unemployment and recession.^[2]

To stimulate the motor industry, a £2,000 scrappage allowance was announced for a car more than 10 years old, if it is traded in for a new car and if it has been in the car buyer's ownership for the previous 12 months. £1,000 of this is to be provided by the government, and £1,000 by a motor manufacturer.^[1] The scheme started about mid-May 2009 and was planned to finish at the end of February 2010; however, before it was due to end, it was extended by one month, to the end of March 2010.^[3]

For high earners, a 50% tax band was announced for earners of over £150,000 per year to start in April 2010,^[1] and tax relief on pension contributions was reduced progressively from 40% to 20% for annual incomes between £150,000 and £180,000 and to 20% above £180,000 commencing April 2011.^[4]

Starting in April 2010, those with annual incomes over £100,000 would see their Personal allowance reduced by £1 for every £2 earned over £100,000, until the Personal allowance was reduced to zero, which (in 2010) would occur at an income of £112,950. This had the effect of creating an anomalous effective 60% marginal tax rate in the income band between £100,000 and £112,950, with the marginal tax rate returning to 40% above £112,950. As the Personal allowance has grown over the years, this has resulted in a corresponding increase in the size of the anomalous effective 60% tax band. As of 2018, the effective 60% marginal tax rate now arises for incomes between £100,000 and £123,700.^{[citation needed]}

For savers, limits in Individual Savings Account (ISA) accounts were increased in two phases to a total of £10,200, including an additional £1,500 to the previous upper limit of £3,600 in a cash ISA. The first phase is for those over age 50 years, who can contribute additional amounts from 6 October 2009.^[1]

• Budget of the United Kingdom