The AIA was introduced in 2008. It is an allowance for tools and equipment meaning a business can write off 100% of qualifying capital expenditure (up to a set limit - currently £500,000) against taxable profits for the same period. (Expenditure over the limit is subject to the normal writing down allowances of 18 or 8 %.)
AIA is available for companies, individuals and partnerships, where all the members are individuals.
It’s available for most assets purchased by a business, such as machines and tools, vans, lorries, diggers, office equipment, building fixtures and computers. It does not apply to cars.