R&D tax claims after the reset: Writing the technical narrative

A technically valid R&D claim can still be undermined by a weak or inconsistent narrative. The technical narrative plays a central role in demonstrating that a claim meets the eligibility criteria, and has been prepared with care.

As part of our ‘Back to basics’ series, this article focuses on the purpose and structure of the technical narrative, and how it should align with the requirements of the Additional Information Form (AIF). If you missed part one on eligibility, you can read it here .

What should the technical narrative cover?

The aim of the technical narrative is to explain clearly why the claim qualifies, addressing HMRC’s expected questions without introducing unnecessary information.

The structure of the narrative should follow the sections of the AIF, which require details of:

the main field of science or technology

the existing knowledge the project sought to advance

the advance being attempted

the technological uncertainties faced

how those uncertainties were addressed

Each qualifying project included in a claim must be described in this way.

Writing an effective technical narrative

When preparing the narrative, we recommend the following:

Stick to the technical facts: HMRC’s focus is on the science and technology. Commercial context should only be included where it is directly relevant to understanding the technical challenge.

Keep it concise: Although each section allows up to 20,000 characters (3-5000 words), most projects do not require that level of detail. Clear, focused explanations are more effective than lengthy descriptions. The best technical narratives tell HMRC exactly what they need to know, and no more.

Avoid unnecessary padding: Background information about the company’s history, commercial success or general business activities does not strengthen a claim and can distract from the qualifying work. It’s best practice to stick to the main points and don’t add anything irrelevant, or go into detail about every tiny problem encountered at each stage of the project.

Focus on the underlying science or technology: The technical narrative should be a technical narrative. It should demonstrate how the work sought to resolve technological uncertainty, rather than information about the commercial aspects of the claimant company’s business, unless it is directly relevant to the claim. Including too much of this kind of information can confuse the narrative and could lead HMRC to conclude that ineligible commercial costs have been included in the claim.

Use clear accessible language: HMRC inspectors are unlikely to be specialists in the relevant field. The narrative should be written in a way that is clear, understandable, and does not use excessive technical jargon. This way, an inspector can understand exactly why the claim is eligible, without having to ask for expert help.

How WhisperClaims supports narrative preparation

WhisperClaims provides a structured approach to narrative preparation, aligned with the AIF requirements. Our platform ensures that all required sections are completed, and that claims cannot progress without the necessary information being captured.

Once complete, WhisperClaims produces both AIF-ready outputs and a formatted technical report that can be reviewed with your clients before submitting to HMRC.

If you missed our recent webinar, “R&D tax claims after the reset: Re-examining eligibility, evidence, costs & benefit”, you can watch back on demand and find out more about how structured narrative preparation supports clarity, consistency and compliance.