Where you purchase plant or machinery for use in your business you are entitled to claim a tax deduction for the cost. This can be spread over many years. However, in a twelve-month period you are entitled claim a tax deduction (capital allowance) for 100% of the cost of assets up to a set amount, known as the annual investment allowance (AIA).
The Flow Chart - Capital Allowances Annual Investment Allowance will help you decide if you are entitled to claim the AIA for the cost of assets.
Definitions for the flow chart:
For HMRC guidance on what counts as plant or machinery visit https://www.gov.uk/hmrc-internal-manuals/capital-allowances-manual/ca21010