A Detailed Guide on R&D Claim Notification Requirements For Businesses in UK

The tax relief scheme for research and development (R&D) offers valuable support to companies in the UK. But the rules for the R&D claim notification form are strict, and failure to follow them may cause your claim to be rejected. Below is a clear summary of what you must do.

What is the R&D Claim Notification Form?

From accounting periods beginning on or after 1 April 2023, companies must submit a “claim notification form” to HMRC if they are:

• claiming R&D relief for the first time, or
  
• their last valid claim was made more than three years before the end of the claim notification period.

The claim notification period starts on the first day of your “period of account” and ends 6 months after its end date.

For example, if your accounting period runs from 1 January 2024 to 31 December 2024, your claim notification window is from 1 January 2024 to 30 June 2025. If you fail to notify within that window, any claim for that period may be invalid. Extra care is needed because HMRC has issued clarifications about transitional cases. 

Key Details: What the Form Requires

When completing the claim notification, your company (or your agent) must include:

• The company’s Unique Taxpayer Reference (UTR) matches the one on the CT600.
• Contact details of the senior internal R&D contact (e.g., company director) and any agent.
• The period of account start and end date; the accounting period start and end date.
• A high‑level summary of your planned R&D activities. This should show how the work meets the standard R&D definition.

The Three‑Year Look‑Back Rule

You may not need to submit the claim notification if your company has submitted a valid R&D claim within the three years ending on the last date of your claim notification period. 

Important caveats:

• A claim for a period starting before 1 April 2023 that is made via an amended return on or after 1 April 2023 does not count for the three‑year exemption.
• If HMRC rejected your previous claim, then that claim is treated as if it did not count.

Additional Information Form (AIF)

Even after submitting the claim notification (if required), you must submit an Additional Information Form (AIF) for the accounting period for which you are claiming.

Key points:

• The AIF must be submitted before or on the same day as your Company Tax Return (CT600). 
• If you file the CT600 before the AIF, HMRC will remove your R&D claim. 

What Happens If You Miss the Deadline?

If you fail to file the claim notification when required, your claim may be rejected by HMRC, and you may lose the right to claim for that accounting period. HMRC has acknowledged some transitional errors (in the guidance), but these apply only in narrow cases. 

How Apex Accountants’ R&D Tax Relief Claim Services Can Help

At Apex Accountants we provide end‑to‑end support for claims related to R&D tax relief. Our services include:

• Support with the claim notification form, verifying if your business needs to submit one and helping you meet the deadlines.
• Preparation of the Additional Information Form (AIF) and submission alongside your CT600.
• Full claim preparation services include assessing eligible projects, gathering costs, and preparing technical narratives.
• Strategic advice on filing options, ensuring that your claim aligns with HMRC’s latest rules.

If you are considering an R&D claim and feel unsure about the paperwork or deadlines, our team is ready to help you manage the process professionally.

FAQs on R&D Claim Notification 

Q1. Do I always need to submit a claim notification form when I make an R&D claim?

No. You only need to submit a claim notification form if you are claiming for the first time or if you have not made a valid claim in the last three years before the claim-notification deadline. 

Q2. When exactly is the deadline to submit the claim notification?

The notification period ends six months after the end of the company’s period of account. 

Q3. If my period of account is more than 12 months (covers 2 accounting periods), does that change the rule?

Yes. If the period of account exceeds 12 months, it may cover two or more accounting periods, but you only need to submit one claim notification for that period of account. 

Q4. What happens if my previous claim was made more than three years ago, but it was for a period before 1 April 2023 via an amended return?

That type of claim does not count for the three‑year exemption. You would need to submit a claim notification form. 

Q5. Can I file the AIF and CT600 after the claim notification?

Yes, but the AIF must be submitted before or on the same day as your CT600. The claim notification must be submitted within its deadline. 

Q6. What information is needed in the claim notification form?

You will need UTR, contact details for the company and agent, accounting period dates, period of account dates, and a high‑level summary of planned R&D activity. 

Q7. If I miss the claim notification deadline, can I still claim?

It is very risky. HMRC guidance says if you fail to notify and you were required to, your claim may be invalid. 

Q8. Does submitting the claim notification guarantee that my R&D claim will be accepted?

No. It merely meets the notification requirement. The claim must still meet the R&D qualifying criteria, and the AIF and CT600 must be properly submitted.

Q9. Are there any transitional reliefs or special cases I should be aware of?

Yes. HMRC corrected previous guidance and allowed some claims where the guidance was incorrect. But the window is narrow and should not be relied upon. 

Q10. How far back can I claim R&D tax relief?

The claim itself must normally be submitted as part of the CT600 or an amendment within one year after the original filing date, but the claim notification requirement is separate and must meet its own deadline.