Facts and sources

R&D tax evidence: what HMRC and the IRS have published.

Where the evidence problem in R&D claims comes from, in the tax authorities' own figures and words. Each statement links to its official source.

Checked against the official texts on 11 October 2026. Educational information only, not tax advice.

United Kingdom

HMRC: claims, compliance and records.

The scale of UK R&D relief

An estimated 40,325 R&D tax relief claims were made for the financial year 2024 to 2025, 17% fewer than the year before. Source
Total support claimed for 2024 to 2025 is estimated at £8.2 billion, on £51.0 billion of qualifying R&D expenditure. Source
HMRC believes a key driver of the fall in claims is the additional information form, mandatory for all R&D claims submitted from 8 August 2023. Source
More than 90% of R&D claimants are represented by an agent. Source

What HMRC found when it checked claims

HMRC's updated estimate of error and fraud across both R&D schemes for 2020 to 2021 was 16.7% (£1.13 billion); for the SME scheme it was 24.4% (£1.04 billion). HMRC has since published updated estimates for later years in its annual reports. Source
In HMRC's random enquiry programme, around half of all claims by volume contained at least some element of non-compliance. Source
A quarter (25%) of the claims examined were fully disallowed because no qualifying R&D activity took place; in 19%, qualifying R&D took place but the relief was overclaimed. Source
Fraud indicators were found in fewer than 10% of the claims examined. HMRC says this indicates that most non-compliance is down to other behaviours. It uses non-compliance to cover everything from mistakes and failure to take reasonable care through to deliberate non-compliance. Source

What HMRC says about records

"It is good practice to keep relevant records from the beginning of the project." Source
"Without records, you may find it harder to identify there was a project and harder to show your expenditure qualifies for relief. This can be a particular problem if staff who worked on the project are no longer available." Source
If HMRC opens a compliance check, it may ask for anything reasonably needed to evidence the claim, including documents showing that a project existed. Source
An additional information form must be submitted to support every new claim, before or on the same day as the Company Tax Return. Without it, the claim will not be accepted. Source

United States

IRS: research credit claims and Form 6765.

What the IRS requires with a research credit claim

A research credit claim for refund must identify all the business components the claim relates to, and all the research activities performed for each business component. Source
It must also give the total qualified wages, supplies and contract research expenses for the claim year, which can be done using Form 6765. Source
Since June 2024 the IRS no longer requires, at filing, the names of the individuals who performed each activity or what each sought to discover, but it may request this information if the claim is selected for examination. Source
The transition period that let taxpayers fix a deficient research credit refund claim within 45 days ran until 10 January 2026. Source

Form 6765 and record keeping

Section G of Form 6765 (business component information) is optional for tax years beginning before 2026 and required for tax years beginning after 2025, subject to its exceptions. Source
Every person liable for federal tax must keep the records the Secretary prescribes, and the Secretary may require any person to keep records sufficient to show whether or not they are liable for tax. Source

What this means

The weak point is evidence made after the event.

HMRC's additional information form asks for a description of each project, a US research credit refund claim must identify each business component and its research activities, and HMRC's guidance favours records kept from the start. Evidence rebuilt months later, from memory or from people who have moved on, is harder to rely on.

Evidante keeps the record as the work happens, from the tools a client's engineers already use, and organises it for the professional who decides what qualifies. It does not decide eligibility and is not endorsed by HMRC or the IRS.

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Questions

Common questions, answered from the sources

What records does HMRC expect for an R&D tax relief claim?

HMRC's guidance (GfC3, part 5) says it is good practice to keep relevant records from the beginning of the project, and that without records it may be harder to show there was a project and that the expenditure qualifies, particularly if the staff involved are no longer available. Every new claim also needs an additional information form, submitted before or on the same day as the Company Tax Return.

What can HMRC ask for in an R&D compliance check?

If HMRC opens a compliance check into an R&D claim, it may ask for anything reasonably needed to evidence the claim, including documents showing that a project existed.

Why are so many R&D claims challenged?

In HMRC's random enquiry programme (2020 to 2021 claims), around half of claims contained at least some non-compliance, a quarter were disallowed in full because no qualifying R&D took place, and fewer than 10% showed indicators of fraud. HMRC says this indicates that most non-compliance is down to behaviours other than fraud, from mistakes to failure to take reasonable care.

What does the IRS require with a research credit claim for refund?

The claim must identify all the business components it relates to, all the research activities performed for each business component, and the total qualified wages, supplies and contract research expenses (which can be given on Form 6765). The IRS may ask who performed each activity and what they sought to discover if the claim is examined.

Is Form 6765 Section G mandatory?

According to the Instructions for Form 6765 (Rev. December 2025), Section G (business component information) is optional for tax years beginning before 2026 and required for tax years beginning after 2025, subject to its exceptions.

What is contemporaneous R&D evidence?

Records made at the time the work was done, such as commit messages, pull requests, build results and ticket updates, rather than accounts written later for the claim. HMRC's guidance recommends keeping relevant records from the beginning of the project.

Is there software that keeps R&D evidence for tax advisers?

Evidante is evidence preservation software for R&D tax practices in the UK and the US. It records activity from a client's engineering tools (GitHub, GitLab, Bitbucket, Jira, Linear, Azure DevOps, Slack and Teams) as the work happens, organises it by client, project and date for the professional's review, and produces a Defence Pack anyone can check for changes. It does not decide whether work qualifies, give tax advice or file claims, and it is not endorsed by HMRC or the IRS.