Best practice in R&D tax relief: what does good look like now?

Author: Jen Badger Published: 9^th September, 2026

Here at WhisperClaims we have always concerned ourselves with making sure our users can make the best possible claims for R&D tax relief. The changes HMRC have made over the past few years, from updating the schemes, to increased compliance activity and new advance assurance options, have meant that best practice has been a constantly evolving concept. Here we bring together the advice we’ve given about each element of producing claims to help you understand what good looks like now.

Ensuring claims are valid

In addition to all the usual eligibility checks, claimants now have to consider both the claim notification form (CNF) and the additional information form (AIF). It’s vital ensure that the AIF is always filled out and submitted before the CT600, and that a CNF is submitted within the correct time frame, where necessary, to ensure that a claim is valid.

Each of these forms has different criteria and requirements, and claim preparation processes must take all of this into account to make sure no claim is missed.

Checking project eligibility

Throughout all of the changes made to the scheme, the one area that has remained constant is HMRC’s definition of R&D for the purposes of R&D tax relief. Qualifying work must still:

be structured as a project;
seek to achieve an advance in science or technology;
involve the resolution of technological uncertainties;
go beyond the baseline of existing science or technology;
be resolved through technical means;
be led by competent professionals.

Best practice in checking eligibility, therefore, remains as it always has been – you must examine each project against HMRC’s definitions and be satisfied it meets all the criteria before including it in an R&D tax relief claim.

Getting feedback from HMRC on eligibility

When assessing eligibility, claimant and advisors now have two ways to get feedback from HMRC through the Advance Assurance services. This means that you can now include getting feedback from HMRC in your eligibility checks for any claim where you have questions or doubts, making claims even more robust and defensible.

EPWs, contracted out R&D and overseas costs

The rules about contracted out R&D, EPWs and overseas costs have undergone fairly radical changes in recent years. Best practice now means:

Assessing all contracted out R&D arrangements against the new rules;
Assessing all EPW costs to establish whether EPWs were paid through UK payroll, and, if not, whether the work might qualify for an exemption to the overseas costs rules, and;
Checking whether contracted out R&D took place within the UK, and, if not, whether the work might qualify for an exemption to the overseas costs rules.

All R&D claim preparation processes must now take account of these rules to ensure that no ineligible costs are included in the claim.

Using AI to prepare claims

Finally, any discussion about best practise has to consider the use of AI in preparing R&D tax relief claims. Here at WhisperClaims we’ve always advised caution when using AI tools. It’s vital to both ensure that all information included in a claim is valid and an experienced advisor checks all AI produced information before it is submitted to HMRC.

Are you confident in your approach to R&D tax relief?

If you’re looking for a way to ensure that all of your claims are prepared according to best practice every time, we’re happy to show you what WhisperClaims’ compliance-first approach looks like in practice.

Let’s talk