United Kingdom: Disputes and appeals | Research Credit Integrity Alliance

This page explains how a company can challenge HMRC when a United Kingdom research and development (R&D) tax relief claim is reduced, removed or refused, and what HMRC has published about R&D disputes. It describes the process only and makes no recommendation.

How a claim comes to be reduced

Most R&D disputes begin with a compliance check. When HMRC completes a check, it either sends one or more decision notices or agrees a contract settlement with the taxpayer. A decision notice can be an assessment or an amendment to an assessment, a penalty notice, or a letter explaining the final position.1 See Reviews and audits.

HMRC states that most tax disputes are resolved collaboratively and by agreement once the facts have been established and the point at issue clarified.2 It reports that 89 percent of the R&D compliance checks it settled in 2023 to 2024 were resolved by agreement with the claimant.2

Where a company claimed enhanced R&D intensive support (ERIS) and HMRC amends the return after an enquiry to remove that claim because the ERIS conditions were not met, the company may make or amend a claim under the merged R&D expenditure credit if its expenditure qualifies. The time limit for doing so is 30 days after the closure notice is issued or, if there is an appeal, 30 days after the appeal is finally determined.3

Claims treated as invalid

Some claims fail without a compliance check, because a required filing is missing or late:

Requirement	Consequence stated by HMRC
Claim notification, where one is required, made within the claim notification period	If it is not made in time, the R&D claim is invalid4
Additional information form submitted before, or on the same day as, the Company Tax Return	If it is not submitted, the claim will not be accepted. If the return arrives before the form, the claim will be rejected and HMRC will write to confirm that it will remove the R&D claim from the return5
Amount of relief or credit quantified when the claim is made	If it is not quantified, or the return is incomplete, there is no valid claim3

HMRC's guidance warns that if a claim is rejected close to the last date for amending the return, the company may not be able to make a valid R&D claim for that accounting period.5 Claims can generally be made, amended or withdrawn up to two years from the last day of the period of account, where that period is not longer than 18 months. HMRC has a discretion to accept late claims, which it exercises only in line with Statement of Practice 5 (2001).3

In one instance HMRC accepted that its own guidance on claim notifications had been wrong. HMRC's manual records that incorrect guidance was published between 8 September 2024 and 17 October 2024, and sets out an administrative easement for companies that meet stated conditions and apply to its R&D Policy team.6

The HMRC guidance pages for the two forms do not describe a separate procedure for challenging the removal of a claim treated as invalid.45

The statutory route: appeal, review and tribunal

Corporation Tax is a direct tax. For direct tax decisions, the taxpayer must appeal to HMRC first.7 The general route is:

Step	What happens	Usual time limit
1. Appeal to HMRC	The company writes to HMRC, or uses the appeal form sent with the decision letter, saying what it disagrees with and why. The officer who made the decision looks at the case again and aims to reach agreement7	30 days from the date of the decision letter7
2. Statutory review	If agreement is not reached, HMRC offers a review. The company can also ask for one at any time after appealing. A review officer from a different team, not involved in the original decision, upholds, varies or cancels the decision7	30 days from the date of the offer to accept the review or appeal to the tribunal. Reviews usually take 45 days7
3. First-tier Tribunal (Tax)	An independent tribunal hears the appeal and can replace the decision with a new one or ask HMRC to look at it again8	Usually 30 days from the date of the review conclusion letter7
4. Upper Tribunal (Tax and Chancery)	An onward appeal is possible only with permission, where the First-tier Tribunal made a legal mistake8	Full written reasons must be requested within 14 days of the decision notice, and permission within 56 days of the date of the full written reasons8

HMRC's internal guidance explains that there is only one appeal, potentially in two stages: first to HMRC, during which a review may take place, and then, if necessary, to the tribunal. A review cannot take place after the appeal has been sent to the tribunal.9 If the company neither accepts an offered review nor notifies the appeal to the tribunal within 30 days, the appeal is treated as settled by agreement under section 49C of the Taxes Management Act 1970.9 The same applies if the appeal is not notified to the tribunal within 30 days of the review conclusion letter, under section 49F of that Act.9

A company that misses a deadline needs to give a reasonable excuse, and a late appeal to the tribunal is accepted only if a judge agrees.78

Alternative dispute resolution

Alternative dispute resolution (ADR) is a non-statutory process in which an HMRC mediator trained in mediation works with the taxpayer and the HMRC officer dealing with the case. The mediator does not take over responsibility for the dispute.10 ADR can be used during a compliance check where progress has stalled, and at the end of a check when an appealable decision has been made. It does not affect the right to appeal or to ask for a statutory review.10 Where HMRC has opened an enquiry, the taxpayer can apply at any stage of the enquiry or of the tribunal proceedings, and an agent can apply for its client. HMRC can reject applications it does not consider suitable.10

Paying while a dispute continues

For direct tax, the company can ask HMRC to delay payment of part or all of the tax in dispute, within 30 days of starting the appeal or review. Interest can be charged on the disputed tax until it is paid. A penalty under appeal does not have to be paid until the appeal is settled.7

Challenging the check itself

A taxpayer who thinks HMRC should stop a compliance check must first tell HMRC why. If HMRC does not agree, the taxpayer may be able to ask the tribunal to decide whether the check should stop.1 The tribunal guidance confirms that a taxpayer can apply to the tax tribunal for an order closing an HMRC enquiry into a return.8

Whether an enquiry was opened in time can also be disputed. In one R&D case, the First-tier Tribunal decided as a preliminary issue whether HMRC's enquiry letter had been received by the last date on which HMRC could open a valid enquiry into a claim for an R&D credit made in an amended return. The Upper Tribunal refused permission to appeal that decision.11

HMRC figures on R&D disputes

HMRC published the following figures for 2023 to 2024:2

Route	Figures reported
Statutory review	822 requests held, some received in 2022 to 2023. Of the 251 concluded, the decision was upheld in 214, varied in 33 and cancelled in fewer than 5
Alternative dispute resolution	153 requests received. Of the cases concluded, 22 were fully resolved, fewer than 5 partly resolved, 12 had the points in dispute clarified, and fewer than 5 reached no resolution
Tribunal	One R&D case went to a tribunal hearing, and it was decided in HMRC's favor

Complaints are a separate route

Complaints about how HMRC handled a case are not appeals. HMRC describes a two tier internal complaints process, after which the customer can ask the Adjudicator's Office to review the complaint, and then ask a Member of Parliament to refer it to the Parliamentary and Health Service Ombudsman.2 ADR cannot be used for complaints about HMRC delays or misleading advice.10 HMRC reported 423 R&D complaints received in 2023 to 2024, and 207 upheld.2

When the agent stops acting

HMRC notes that some agents who advised a customer or made a claim for it are unwilling to engage with a later compliance check. In that case HMRC says the claimant should contact HMRC directly to resolve the check, and it reminds customers that they remain responsible for their own tax affairs even when they use an agent.2 HMRC's internal guidance requires a letter offering a review, and a review conclusion letter, to be sent directly to the customer even where HMRC has been dealing with an agent, with a copy to the agent where appropriate.9

Sources

HM Revenue and Customs, About compliance checks: CC/FS1a (updated 30 April 2025), sections "If you think we should stop the compliance check", "What happens at the end of the compliance check" and "If you disagree". https://www.gov.uk/government/publications/general-information-about-compliance-checks-ccfs1a/about-compliance-checks-ccfs1a (accessed 11 October 2026). Back
HM Revenue and Customs, Approach to Research and Development tax reliefs 2023 to 2024 (published 30 October 2024), section 2.4, "Concluding the compliance check", "Compliance checks: facts and figures", "Dispute Resolution", "Maintaining standards" and Table 5, and section 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
HM Revenue and Customs, Corporate Intangibles Research and Development Manual, CIRD181000, "R&D Tax Reliefs: reformed reliefs: claims process: overview" (manual updated 25 August 2026), sections "Claim Requirements" and "Time limits". https://www.gov.uk/hmrc-internal-manuals/corporate-intangibles-research-and-development-manual/cird181000 (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), section "When to submit the form: claim notification period". 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, Additional information you must submit before you claim Research and Development tax relief (last updated 26 September 2025), section "When to submit". 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, CIRD183000, "R&D Tax Reliefs: reformed reliefs: claims process: pre-notification of claims" (manual updated 25 August 2026), section "Administrative Easement". https://www.gov.uk/hmrc-internal-manuals/corporate-intangibles-research-and-development-manual/cird183000 (accessed 11 October 2026). Back
GOV.UK, Disagree with a tax decision or penalty, sections 2 "Disagree with a tax decision", 3 "Disagree with a penalty", 4 "Get a review", 5 "Delay payment during appeals and reviews" and 6 "Reasonable excuses". https://www.gov.uk/tax-appeals/print (accessed 11 October 2026). Back
GOV.UK, Appeal to the tax tribunal, sections 1 "Overview" (including "Close an enquiry"), 2 "Appeal to the tribunal", 3 "If you have a hearing" and 4 "The tribunal's decision". https://www.gov.uk/tax-tribunal/print (accessed 11 October 2026). Back
HM Revenue and Customs, Appeals, Reviews and Tribunals Guidance, ARTG2010, "Reviews and appeals overview: Process for direct taxes" (manual updated 18 September 2026), sections "General", "Customer's rights", "HMRC offer of a review", "Conduct of review" and "Options following review". https://www.gov.uk/hmrc-internal-manuals/appeals-reviews-and-tribunals-guidance/artg2010 (accessed 11 October 2026). Back
HM Revenue and Customs, Use alternative dispute resolution to settle a tax dispute (last updated 24 January 2024), sections "How alternative dispute resolution works", "What alternative dispute resolution can be used for", "When you can apply" and "How to apply". https://www.gov.uk/guidance/tax-disputes-alternative-dispute-resolution-adr (accessed 11 October 2026). Back
Upper Tribunal (Tax and Chancery Chamber), Assembly Global Networks Ltd v The Commissioners for His Majesty's Revenue and Customs [2025] UKUT 00023 (TCC), decision of 16 December 2024, paragraphs 2 and 39. https://www.gov.uk/tax-and-chancery-tribunal-decisions/assembly-global-networks-ltd-v-the-commissioners-for-his-majestys-revenue-and-customs-2025-ukut-00023-tcc (accessed 11 October 2026). Back