Do evidence-based R&D tax claims give you confidence?

R&D tax relief exists to encourage innovation across the UK, and at its best, it delivers valuable support to companies pushing technological boundaries. Yet in recent years, as HMRC has increased the depth and frequency of its enquiries, many businesses have found themselves approaching claims with more caution. In our experience, this heightened scrutiny has affected a broad range of claimants – even university spin‑outs undertaking clearly defined scientific R&D have encountered enquiries that take considerable time and effort to resolve.

For businesses of all types, this raises the same question: how can you prepare a claim that feels well‑grounded, transparent, and capable of standing up to detailed review?

Why evidence matters in an R&D tax claim

Typically, R&D projects will generate some form of contemporaneous documentation. This might include project plans, experimental results, design documents, process data, or prototypes. Using this material as the foundation of a claim ensures that project descriptions are clear, specific, and reflective of what actually took place during the accounting period.

This evidence also plays a key role in supporting the financial aspects of a claim. Linking costs – such as consumables, externally provided workers, or subcontracted activities – directly back to documented R&D activity, the rationale for their inclusion becomes transparent and easier to justify.

An evidence‑based approach therefore strengthens both the technical and financial components of a claim – and creates a foundation that is far easier to support should HMRC request further details.

The risks of relying on assumptions

HMRC expects that costs are attributed on a just and reasonable basis. Gaps in documentation or assumptions that lack a clear methodology can leave a claim more vulnerable to challenge.

Where costs must be apportioned after the fact, it becomes more difficult to support their inclusion. Whilst there are approaches that can be used to help justify these costs, to be fully defensible they would have to be built upon a logical extension of what information is available. Ultimately, the less thought and effort put into estimations, the more fragile they are.

For example, in an ideal world staff costs would be based exclusively on time record keeping. Where this is not available, an evidence based approach to time estimation could be used, basing a percentage of employees’ time on documented project start and end times, meeting logs, experimental records, or process run times. However, estimating a percentage without having a justifying principle behind it makes the figure questionable, and open to challenge.

Why strong documentation builds confidence

Without supporting evidence, an R&D claim is on fragile ground. However, when prepared considering and with reference to contemporaneous documentation, the rationale behind each claimed cost becomes traceable and the entire claim auditable.

What’s more, when ensuring that these records are kept throughout the year, claim preparation becomes less burdensome. By ensuring that individual costs are tracked to specific projects, and by properly logging any R&D progress reports throughout the year, the collection of the proof needed to justify a claim after the end of an accounting period becomes a much simpler exercise.

Through establishing a solid evidential grounding, claims can be submitted with confidence, both from the perspective of knowing that your claim meets HMRCs rigorous standards as well as enabling planning to be made around the resultant tax credit.

How AAB’s approach builds confidence in an R&D tax claim

Our expert R&D specialists work closely with both technical and financial teams to understand the detail of the innovation being undertaken. We review project documentation, explore how activities link to the legislation, and help ensure the claim is supported by clear, verifiable evidence.

Beyond preparing the claim itself, we work with clients to improve the way information is captured through the year – enhancing compliance, improving efficiency, and reducing uncertainty in future submissions.

By addressing key questions early, we help businesses submit claims with confidence in their accuracy and defensibility.

What level of detail does HMRC expect?

Precision is one of the strongest tools when preparing R&D project descriptions. Aligning narratives to the definition of R&D for tax purposes within the DSIT guidelines – articulating the technological or scientific advance being sought and the corresponding uncertainties – allows HMRC to understand the basis of the claim quickly and clearly.

Referencing contemporaneous documentation within the narrative, such as test runs, experiment logs, meeting notes, or milestone achievements (including dates where possible), helps create a short but compelling timeline of activity. It also signals the specific evidence available should HMRC request it.

On the financial side, demonstrating how costs relate to project activities shows that expenditure has been allocated thoughtfully and appropriately. In both narrative and numbers, quality matters more than quantity.

Better claims, better decisions, better outcomes

When the numbers and the narrative are based upon verifiable evidence, R&D tax relief can once again become part of your wider planning. You can forecast with more certainty whilst feeling more secure about the cash impact on your business. By establishing the tools, records and habits that can be used to underpin a claim, you gain assurance that a credit is justifiable, both now and into the future.

R&D inherently involves risk, but R&D tax credit applications need not be risky. With our support you can claim with confidence, control and clarity, allowing more focus to be given towards supporting your teams and cementing the innovative work of your business. If you have any queries about your R&D tax credit claim please do not hesitate to get in contact with Matthew Millyard, Naeem Desai or your usual AAB contact.