HMRC Pre-Notification for R&D Claims

by Adam Park | February 26, 2026

If your business plans to claim R&D tax relief, you must pre-notify HMRC before submitting your claim. This rule applies to accounting periods starting on or after 1 April 2023. The notification must be submitted within six months after the end of your accounting period. Missing this deadline results in automatic rejection of your claim, even if it qualifies.

Key Points:

Who Needs to Notify: First-time claimants or those who haven’t claimed in the last 3 years.
How to Notify: Submit a digital form via HMRC’s online portal with details like your UTR, senior contact, and a brief R&D summary.
Deadline: Six months after the end of your accounting period (e.g., for a period ending 31 December 2024, the deadline is 30 June 2025).
Consequences of Missing the Deadline: Claims will be rejected with no option to appeal.

This step aims to reduce fraud and errors in R&D claims, which cost HMRC £1.13 billion in 2020–21. If you're unsure about eligibility, it's safer to notify as a precaution.

HMRC R&D Tax Relief Pre-Notification Process and Timeline

What is the Pre-Notification Requirement?

The pre-notification requirement is a step businesses must complete before submitting an R&D tax relief claim. It’s not the claim itself but an advance notice to HMRC of your intention to claim. This is done digitally through HMRC’s online portal using your Government Gateway account. The form asks for key details such as your company’s UTR, a senior R&D contact, any agent details (if applicable), and a concise summary (up to 10,000 characters) of your R&D activities. Once submitted, make sure to save the confirmation email and reference number, as you won’t be able to access the form later.

Why HMRC Introduced Pre-Notification

The primary reason HMRC introduced this process was to address fraud and errors in R&D tax relief claims. For the 2020-2021 period alone, HMRC estimated that fraud and error accounted for 16.7% of R&D reliefs, totalling £1.13 billion. The SME scheme was particularly affected, with a non-compliance rate of 24.4%, equalling £1.04 billion. First-time claimants were found to have higher non-compliance rates compared to repeat claimants.

Victoria Atkins MP, Financial Secretary to the Treasury, explained:

The Regulations deliver on the government's commitment to tackle high levels of fraud and error within the R&D tax regimes by improving the standard of information that companies are required to provide in support of their claims.

Beyond fraud prevention, the requirement also enables HMRC to guide new and infrequent claimants more effectively. It also helps protect businesses from unscrupulous agents who might encourage non-compliant or questionable claims. To reinforce these efforts, HMRC has doubled its compliance workforce over the last three years, adding 300 specialised staff to focus on non-compliance. These measures highlight HMRC’s goal of improving claim accuracy and reducing risks.

When Pre-Notification Applies

Knowing when pre-notification applies is crucial to ensure your claim isn’t rejected.

This requirement applies to all accounting periods beginning on or after 1 April 2023. If your accounting period started before this date, you’re exempt from pre-notification, even if it ends after 1 April 2023. The notification window opens on the first day of your accounting period and closes six months after its end. For instance, if your accounting period runs from 1 January 2024 to 31 December 2024, you must submit your pre-notification by 30 June 2025.

This six-month deadline is much earlier than the standard two-year timeframe for submitting the actual R&D claim. As a result, businesses need to identify and document their R&D activities much sooner, marking a shift in how they approach R&D tax relief planning.

Which Businesses Must Pre-Notify HMRC?

Understanding the pre-notification process is essential for businesses looking to claim R&D tax relief. Only specific businesses need to notify HMRC in advance, so confirming your eligibility is crucial to avoid having your claim automatically rejected.

Criteria for Pre-Notification

First-time claimants
If your company has never claimed R&D tax relief before, you must submit a pre-notification. This rule applies to all R&D schemes.
Infrequent claimants
If your business hasn’t submitted a valid R&D claim in the three years leading up to the end of your notification period, pre-notification is required. For instance, if your accounting period runs from 1 January 2024 to 31 December 2024, the notification period ends on 30 June 2025. In this case, you’d need to check whether a valid claim was submitted between 30 June 2022 and 30 June 2025.
Businesses with rejected claims
If HMRC has previously removed your R&D claim from your Company Tax Return, it won’t count towards the three-year exemption. In such cases, pre-notification is still necessary.

It’s also worth noting that submitting an amended return for an accounting period ending before 1 April 2023, but filed after this date, does not meet the pre-notification requirement.

Carol Johnson, Tax Partner at KPMG, highlights the risks:

Failure to pre-notify HMRC of an intention to make a claim for a period that one is due can mean any subsequent claim for that period is rejected by HMRC, so the consequences can be severe.

Interestingly, data from 2020–21 shows a non-compliance rate of 38% for first-time claimants compared to 22% for repeat claimants. This gap underscores HMRC’s stricter rules on pre-notification.

When Pre-Notification is Not Required

On the flip side, you don’t need to pre-notify HMRC if you’ve submitted a valid R&D claim within the three years before the end of your notification period. Additionally, if you file your full R&D claim on your Company Tax Return within six months of your accounting period end, the pre-notification step is unnecessary.

Temporary relief has also been introduced for businesses affected by unclear guidance issued between 8 September 2024 and 17 October 2024. If your notification period ended between 8 September 2024 and 30 November 2024 - and you relied on an amended return for a period starting before 1 April 2023 - HMRC may still accept your claim without pre-notification.

Jenny Trunks, Corporate Tax Manager at MHA, stresses the importance of understanding this requirement:

This latest requirement will be particularly crucial for companies who haven't claimed the relief before or haven't claimed relief for a few years.

When in doubt, it’s safer to submit the pre-notification. Doing so doesn’t commit you to making a claim, but failing to notify when required will lead to automatic rejection.

How to Submit a Pre-Notification

To follow HMRC's pre-notification process, you’ll need to submit the form online through the Government Gateway. Accessing the system requires a Government Gateway user ID and password.

The submission must be handled by a director, senior officer, or an authorised R&D agent. Once logged in, the system provides step-by-step guidance to complete the form. Keep in mind, you won’t be able to view or edit the form after submission. Karen Evans, an R&D Tax Relief Specialist at The R&D Community, highlights this crucial point:

The notification must be made using the digital form within the prescribed time limit.

Before hitting submit, make sure to save or print a copy of the completed form. After submission, HMRC will email you a confirmation with a reference number. This reference is essential for any future correspondence with HMRC regarding your notification.

Information Needed for the Form

Accuracy is key when filling out the form. All information must align perfectly with your CT600 Company Tax Return to avoid discrepancies that could invalidate your claim. Here’s what you’ll need:

Unique Taxpayer Reference (UTR): This must match the UTR on your CT600.
Start and end dates: Include the dates for both your financial statements (period of account) and your accounting period. These must be identical to the dates on your Company Tax Return. For instance, if your accounting period is 1 January 2024 to 31 December 2024, those exact dates should appear on the form.
Contact details for a senior officer: This is typically someone like a director, CTO, or head of finance who oversees the R&D claim.
Details of all R&D agents: List contact information for any agents involved in your claim, whether they provided advice, analysed costs, or prepared technical assessments.

Additionally, you’ll need to include a high-level summary of your planned R&D activities. This summary should explain how your project qualifies as R&D and must stay within 10,000 characters. At this stage, you’re not required to submit evidence or cost documentation - that comes later with the Additional Information Form.

Deadlines for Submission

Timing is critical. The pre-notification must be submitted within six months after the end of your period of account. The notification window opens on the first day of your period of account and closes six months later.

For example, if your accounting period runs from 1 January 2024 to 31 December 2024, the submission window opens on 1 January 2024 and closes on 30 June 2025.

If your period of account exceeds 12 months, the deadline remains six months after the end of the full period. In such cases, you only need to submit one form that covers all accounting periods within that timeframe.

What Happens if You Miss the Deadline

Now that we've covered how to submit your pre-notification, it's important to grasp what happens if you miss the deadline. Submitting your pre-notification on time is critical to keeping your R&D claim valid.

Effect on Your R&D Claim

Failing to meet the pre-notification deadline means your R&D claim will be automatically rejected by HMRC. Even if your project meets all the criteria for relief, your claim will not be considered, and there is no way to appeal this decision.

Jenny Trunks, Corporate Tax Manager at MHA, explains:

Any R&D claim submitted to HMRC without first notifying will be removed from the company tax return and the relief will be denied, regardless of whether the claim is eligible.

The deadline for pre-notification is six months after the end of your accounting period. Emma Hussey, Associate Director at Azets, highlights the importance of acting promptly:

Missing this deadline will mean you are not eligible to claim R&D relief for that accounting period. There is no legislative recourse or statutory right of appeal, so it is essential to act in time.

If you're unsure whether your project qualifies, it's better to submit the notification anyway. There’s no penalty for notifying and later deciding not to file a claim. However, for certain periods, there is a limited administrative exception.

Temporary Relief for 2024 Periods

For cases where the notification deadline falls between 8 September 2024 and 30 November 2024, HMRC has introduced an administrative exception. This applies if you submitted a valid amended return for:

A period starting before 1 April 2023, or
A period beginning between 1 April 2023 and 30 November 2024.

Katy Long, Director at ForrestBrown, explains:

HMRC has confirmed an 'administrative easement' under which it will permit R&D claims by affected companies that haven't notified.

To take advantage of this relief, you’ll need to contact HMRC's R&D Policy team. Use the subject line "CIRD183000 notification" and include the required details. Keep in mind, HMRC won’t apply this exception automatically - you must reach out to them directly.

How Zest R&D Tax Advisors Can Help

Missing deadlines for R&D tax claims can have serious consequences, but with the right guidance, the process can become far less daunting. HMRC’s pre-notification process is strict - missing it could mean losing out on your R&D claim altogether. That’s where Zest R&D Tax Advisors steps in, offering practical support to help your business stay compliant and make the most of your R&D tax relief.

Pre-Notification Compliance Support

HMRC’s deadlines leave no room for error, and Zest ensures your pre-notification is both accurate and on time. They begin by assessing whether your business needs to submit a Claim Notification Form. If required, they handle the submission through the Government Gateway, ensuring it meets the six-month deadline.

Zest doesn’t stop there. They help define your project’s scope, distinguishing between activities eligible for relief and those that aren’t. They also complete the Additional Information Form (AIF), which includes the technical summaries and cost breakdowns HMRC expects.

Claim Preparation and Submission

Once compliance is in place, Zest focuses on strengthening your claim through detailed preparation and submission. They create precise technical summaries that highlight your technological advancements. Additionally, they prepare cost breakdowns, covering everything from staff time records to subcontractor invoices, ensuring all figures match your profit and loss statements.

Zest works closely with your accountant to finalise every piece of documentation. Typically, they complete all R&D tax claim paperwork within two weeks of the initial review meeting and the confirmation of necessary information. If HMRC raises an enquiry, Zest defends your claim at no extra cost. Their fee is straightforward - a single percentage fee based on the amount you successfully claim.

Summary

If you're a first-time or infrequent claimant for R&D tax relief and your accounting period starts on or after 1 April 2023, you must notify HMRC digitally within six months of your accounting period's end. Failing to meet this deadline will result in your R&D claim being rejected outright.

The notification form focuses on key details that align with your Company Tax Return. You'll need to provide your Unique Taxpayer Reference (UTR), contact details for a senior R&D representative, any agent information (if applicable), and a concise summary of your planned R&D activities - limited to 10,000 characters. However, if you've submitted a valid R&D claim within the three years leading up to your notification deadline, you don't need to pre-notify. Determining this exemption can be tricky, especially when amended returns or updated guidance come into play.

HMRC has reported that 16.7% of R&D claims in 2020–2021 included errors or fraud, amounting to around £1.13 billion. To address this, HMRC has more than doubled its compliance staff for R&D claims. For SMEs, the error rate was even higher at 24.4%, with 25% of claims entirely disallowed due to a lack of qualifying R&D activities. These figures underline the importance of ensuring your pre-notification and claim are accurate and compliant.

Zest R&D Tax Advisors offers end-to-end support for the pre-notification process, from determining whether you need to notify to preparing technical summaries that meet HMRC's standards. Their service operates on a single percentage-based fee, charged only on successful claims.

FAQs

Do I need to pre-notify if I claimed R&D relief a few years ago?

If you’ve claimed R&D relief in the past and pre-notification wasn’t a requirement at the time, you generally don’t need to pre-notify now. However, for new or infrequent claimants, pre-notification is required for accounting periods beginning on or after 1 April 2023. This also applies if your circumstances have changed or if HMRC has previously rejected any of your claims.

What counts as a “valid” R&D claim for the 3-year exemption?

To qualify for the 3-year R&D exemption, your claim must align with HMRC’s requirements. This involves submitting the necessary claim notification within the designated timeframe, including a concise summary of the planned activities. Additionally, new or infrequent claimants must adhere to pre-notification rules. Staying up to date with HMRC’s latest guidance is essential to ensure your claim meets all criteria.

Can I fix it if I miss the 6-month pre-notification deadline?

If you miss the 6-month pre-notification deadline, there’s no formal process to appeal or amend this. To stay eligible for R&D tax relief, it’s essential to meet this deadline. Acting quickly ensures you comply with HMRC’s rules.