From 8 August 2023, all R&D tax relief claims must include a mandatory Additional Information Form. HMRC is now rejecting claims without it—here's what practitioners need to know.
HMRC's New R&D Relief Guidance: What the Additional Information Form Means for Your Clients
The landscape of Research and Development tax relief claims is tightening.
HMRC has released new guidance to help companies identify whether projects are eligible for Research & Development tax relief, with particular emphasis on a mandatory compliance requirement that practitioners and their clients need to understand now.
The Additional Information Form is Non-Negotiable
From 8 August 2023, all companies making R&D tax relief claims must complete an additional information form (AIF) to accompany the claim. This requirement is not discretionary, and HMRC has provided guidance on who can submit the AIF and the additional information required. Yet evidence suggests many practitioners and claimants remain unfamiliar with what HMRC now expects—and HMRC is taking enforcement action against those who submit claims without it.
HMRC's Enforcement Approach
The new guidance comes with teeth. HMRC has already been removing invalid claims, submitted without the AIF. This is a material shift in HMRC's administration of the R&D scheme. Claims that lack the AIF are no longer being processed; they are being rejected outright. For practices with clients awaiting R&D relief claims or considering submitting retrospective claims, this reinforces an urgent message: the AIF is not a box-ticking exercise—it is a gateway to claim acceptance.
Practical Implications for Practitioners
The new guidance signals that HMRC intends to raise the bar for R&D relief claims going forward. The R&D scheme, worth billions annually to the UK's innovation sector, has faced sustained criticism for lacking sufficient governance and transparency. The mandatory AIF requirement is HMRC's mechanism to tighten that governance without waiting for legislative reform.
For practitioners, this means:
Timing. If you have clients with open or pending R&D relief claims, verify immediately whether an AIF has been submitted. If not, prepare to submit one or expect the claim to be rejected.
Documentation. The additional information form requires claimants to provide deeper detail about the nature of their R&D projects, the uncertainties they faced, and the technological scope of their work. This is not boilerplate—HMRC expects substance and specificity.
Due diligence. Before advising a client to make an R&D relief claim, ensure that the project genuinely qualifies under ITTOIA 2005 section 105A or CTA 2009 schedule 5. The new guidance will help, but only if you engage with it thoroughly. Generic claims are now even riskier.
The Broader Context
Since 2020, and the increased scrutiny of R&D, the number of R&D cases heard by First-tier Tribunals has risen, with six FTT decisions involving R&D tax relief published in 2024. HMRC's investment in guidance, enforcement, and litigation around R&D relief is not diminishing—it is accelerating. The AIF requirement is part of a coherent strategy to validate claims upstream and reduce disputes downstream.
Next Steps
Practitioners should:
- Review HMRC's updated R&D relief guidance and understand the AIF requirements in detail.
- Audit any active R&D relief claims or proposed claims for compliance with the AIF requirement.
- Update client advisory processes to include explicit AIF preparation as a pre-filing step.
- Ensure new clients understand that R&D relief claims are now subject to stricter documentation standards than they may have experienced in prior years.
The message from HMRC is clear: R&D relief remains available, but the path to claiming it is now narrower and more closely monitored. For practices supporting innovative UK businesses, getting this right is both a compliance necessity and a competitive advantage.