United Kingdom: Claim integrity measures | Research Credit Integrity Alliance

This page lists the forms, notifications and information HMRC requires in support of a United Kingdom research and development (R&D) tax relief claim, and the related measures introduced since 2021. It describes the rules only and makes no recommendation.

Background

HMRC's published estimates put error and fraud in the R&D reliefs at £1.3 billion, or 17.6 percent of the £7.6 billion claimed, in 2021 to 2022.1 HMRC produced a lower, illustrative estimate of 7.8 percent for 2023 to 2024, which it said reflected policy and operational changes and is more uncertain.1 The Comptroller and Auditor General qualified his opinion on the regularity of HMRC's 2023 to 2024 resource accounts because of the material level of error and fraud in Corporation Tax R&D reliefs.2

Measures in force

HMRC lists the following policy changes:1

Measure	Applies from
PAYE-related cap on the size of claims by SMEs	Accounting periods from April 2021
Advance notification of claims to HMRC	Accounting periods from April 2023
Notifying HMRC of a named company officer responsible for the claim and of any advisers used in compiling it	Claims from August 2023
Making claims digitally and providing additional information	Claims from August 2023
Ending nominations of R&D tax credit payments, and new assignments	Claims from April 2024; assignments from November 2023

Each is described below.

Claim notification

For accounting periods beginning on or after 1 April 2023, a company must submit a claim notification form if it is claiming for the first time, or if its last claim was made more than three years before the last date of its claim notification period.3 The period starts on the first day of the period of account and ends six months after the end of the period of account. If a required notification is not made in time, the claim is invalid.3 The form asks for the company's details, the senior internal R&D contact, the contact details of all agents involved and a summary of the planned activities.3 See Claim notification.

Additional information form

For claims made on or after 8 August 2023, the company must provide the information specified in Schedule 2 to SI 2023/813 on or before the date the claim is made. If it is not provided, the claim is invalid.4 The form must be submitted before, or on the same day as, the Company Tax Return, and before the return if both are sent the same day.5 It asks for company details, contact details for the senior officer and all agents, qualifying expenditure by category, and a description of the main projects.45 See Additional Information Form.

HMRC's manual states that answers must address the question asked, that referring to documents held outside the form, such as "see R&D report", is not acceptable, and that incomplete or improper responses increase the likelihood of an enquiry.4

Digital claims

HMRC says that, before the August 2023 changes, around half of claimants did not provide any extra information alongside their claim, and that requiring all claims to be made digitally means the information can be examined more easily.1

Payment to the claimant company

For claims made on or after 1 April 2024, HMRC will generally pay R&D tax credits only to the claimant company, which must give its own payment details on the CT600. The exceptions are for connected party nominees and exceptional circumstances.6 New assignments of R&D tax credit payments made on or after 22 November 2023 are void, subject to a transitional exception.6 See Fee rules.

PAYE cap

Under the merged scheme and ERIS, the credit a company receives for an accounting period cannot exceed the PAYE cap unless the company is exempt. The cap is £20,000 plus 300 percent of the company's relevant PAYE and National Insurance contributions liabilities for the period.7

Advance assurance

HMRC's guidance states that an SME may be able to apply for advance assurance to confirm its claim will be accepted.7

Guidance and education

HMRC published Guidelines for Compliance on R&D in October 2023 to help claimants avoid common mistakes.1 In July 2023 it wrote to around 7,500 care home companies about the criteria for qualifying R&D claims, including what to do if approached by an agent offering to submit a speculative claim in return for high commission.1

Measures directed at advisers

Measure	Description
HMRC standard for agents	HMRC's non-statutory expectations of all agents, including agents who help clients claim reliefs8
Reporting route	Since September 2025, agents and accountancy professionals can report another agent suspected of poor R&D service standards9
R&D Professional Bodies mailbox	A route for professional bodies to raise R&D matters and breaches of standards with HMRC1
Agent Educational Model	Agents identified as submitting multiple claims with similar risks are assigned an HMRC Agent Relationship Manager1
Mandatory registration	Paid advisers who interact with HMRC for clients must register for an agent services account, in stages from 202610
Sanctionable conduct penalties	For conduct on or after 1 April 2026, penalties on tax advisers who act with the intention of bringing about a loss of tax revenue11

HMRC also says its R&D Anti-Abuse Unit has worked since 2023 with the Advertising Standards Authority to remove false advertising by agents claiming to be HMRC-approved, and has contacted agents not registered for anti-money laundering supervision.1

Rate changes

The National Audit Office records that the Finance Act 2023 raised the RDEC rate from 13 percent to 20 percent and reduced the SME additional deduction from 130 percent to 86 percent and the SME payable credit rate from 14.5 percent to 10 percent, from April 2023. It states that the legislation was in part a response to the higher estimated level of error and fraud in the SME scheme.2

What the measures do not cover

None of the forms described in HMRC's guidance asks how an agent is paid.34 HMRC states that it does not regulate tax agents, including those who advise on R&D claims.1

Sources

HM Revenue and Customs, Approach to Research and Development tax reliefs 2023 to 2024 (published 30 October 2024), sections 1.2, 2.1 (Table 2), 2.2 (Table 3), 2.3 and 2.5. https://www.gov.uk/government/publications/hmrcs-approach-to-research-and-development-tax-reliefs-2023-to-2024/approach-to-research-and-development-tax-reliefs-2023-to-2024 (accessed 11 October 2026). Back
National Audit Office, Report by the Comptroller and Auditor General: HM Revenue & Customs 2023-24 Accounts, paragraphs 2.9, 2.18 and 2.19. https://assets.publishing.service.gov.uk/media/6889f286048fff613a4d5b72/Report_by_the_Comptroller_and_Auditor_General.pdf (accessed 11 October 2026). Back
HM Revenue and Customs, Tell HMRC you want to claim Research and Development (R&D) tax relief (last updated 31 October 2024), sections "Who needs to submit the form", "When to submit the form", "Working out your claim notification period" and "What information you'll need". https://www.gov.uk/guidance/tell-hmrc-that-youre-planning-to-claim-research-and-development-rd-tax-relief (accessed 11 October 2026). Back
HM Revenue and Customs, Corporate Intangibles Research and Development Manual, CIRD182000, "R&D Tax Reliefs: reformed reliefs: claims process: additional information form" (updated 25 August 2026), sections "Statutory framework", "What information is required" and "Failure to provide complete or proper responses". https://www.gov.uk/hmrc-internal-manuals/corporate-intangibles-research-and-development-manual/cird182000 (accessed 11 October 2026). Back
HM Revenue and Customs, Additional information you must submit before you claim Research and Development tax relief (last updated 26 September 2025), sections "When to submit", "Company details to include" and "Project details to include". https://www.gov.uk/guidance/submit-detailed-information-before-you-claim-research-and-development-rd-tax-relief (accessed 11 October 2026). Back
HM Revenue and Customs, Corporate Intangibles Research and Development Manual, CIRD81805, "R&D tax relief: conditions to be satisfied: restriction of nominations and assignments" (updated 25 August 2026). https://www.gov.uk/hmrc-internal-manuals/corporate-intangibles-research-and-development-manual/cird81805 (accessed 11 October 2026). Back
HM Revenue and Customs, Research and Development (R&D) Tax Relief: the merged scheme and enhanced R&D intensive support (last updated 8 January 2026), sections "If your credit exceeds the PAYE cap" and "What you need to do next". https://www.gov.uk/guidance/research-and-development-rd-tax-relief-the-merged-scheme-and-enhanced-rd-intensive-support (accessed 11 October 2026). Back
HM Revenue and Customs, The HMRC standard for agents (updated 9 February 2026), sections 1 and 1.1. https://www.gov.uk/government/publications/hmrc-the-standard-for-agents/the-hmrc-standard-for-agents (accessed 11 October 2026). Back
HM Revenue and Customs, Reporting poor R&D tax relief service standards (published 26 September 2025). https://www.gov.uk/guidance/reporting-poor-rd-tax-relief-service-standards (accessed 11 October 2026). Back
HM Revenue and Customs, Check if and when you need to register as a tax adviser with HMRC (last updated 3 September 2026), sections "Who needs to register" and "When to register". https://www.gov.uk/guidance/check-if-and-when-you-need-to-register-as-a-tax-adviser-with-hmrc (accessed 11 October 2026). Back
HM Revenue and Customs, Compliance Handbook, CH176100, "Sanctionable conduct by tax advisers: Overview", and CH176140, "Commencement date" (manual updated 7 October 2026). https://www.gov.uk/hmrc-internal-manuals/compliance-handbook/ch176100 (accessed 11 October 2026). Back