Definition
The Additional Information Form, known as the AIF, is a structured digital submission to HMRC that must accompany every UK research and development tax relief claim filed on or after 8 August 2023. The form requires the claimant to disclose detailed information about the projects, the qualifying expenditure, the senior technical contact responsible for the claim, and the agent, if any, who prepared it. Without a validly submitted AIF, the associated corporation tax return is treated as if the claim had never been made and HMRC will remove the relief.
How HMRC defines it
HMRC sets the AIF requirement in Schedule 1 of Finance (No. 2) Act 2023 and documents the procedure in the Corporate Intangibles Research and Development manual at CIRD81800 onwards. The form is submitted through the HMRC Government Gateway before the CT600 that contains the claim. HMRC specifies that a minimum of one project must be described in full where three or fewer projects exist; where four to ten projects exist, at least three must be described; and where more than ten exist, ten projects covering the majority of expenditure must be described.
Practical example
A software SME claiming relief for two projects in its year ended 31 December 2024 submits the AIF before filing its CT600. The form identifies both projects, describes the scientific or technological advance and uncertainty for each, and lists the qualifying expenditure by cost category. Omitting the AIF would cause HMRC to reject the claim entirely, even if the underlying expenditure is valid.