Claim Notification (Pre-Notification) for R&D Tax Reliefs - What You Must Know
Introduction
In tandem with the Merged Scheme reforms, HMRC has introduced a mandatory claim notification (pre-notification) requirement for most R&D tax relief claims for accounting periods beginning on or after 1 April 2023. This procedural gate is designed to weed out speculative or opportunist claims early in the cycle. Failure to comply can invalidate a claim entirely.
This article explains who must notify HMRC, when and how to do so, key exemptions, critical nuances, and illustrative examples to guide compliant claim strategies.
What Is Claim Notification?
Also known as “pre-notification” or the “Claim Notification Form (CNF)”.
For accounting periods starting on or after 1 April 2023, claimants must notify HMRC of their intention to make an R&D claim within six months of the period end.
The form collects basic company details, the senior internal contact for the R&D claim, and a brief high-level outline of the R&D activities envisaged.
Who Needs to File Notification?
You must submit the notification if:
You are claiming R&D for the first time under the new regime.
You have not made an R&D claim in the three years prior to the end of the claim notification period.
If your last claim was made for a period beginning before 1 April 2023 but was amended after 1 April 2023, notification may be required.
If your previous claim was rejected or removed by HMRC, you may lose eligibility for the three-year exemption and need to notify.
You are exempt from notification if:
You submitted a valid R&D claim within the three years before the last date of the claim notification period.
The claim was originally part of the filed CT600 (not via amendment) and within the three-year window.
When Must Notification Be Submitted?
The claim notification period begins on the first day of the period of account and ends six months after the period of account’s end date.
For accounting periods longer than 12 months, the same notification period applies across all component CT periods.
Example: A company with period from 1 January 2024 to 31 December 2024 would have to notify between 1 January 2024 and 30 June 2025.
Why Did HMRC Introduce It?
To reduce speculative or invalid claims entering the system.
To force claimants to commit to an intention to claim early, increasing transparency and reducing last-minute reconstructions.
As part of a broader package of reforms alongside AIF, more detailed evidential expectations, and enhanced compliance resources.
Key Nuances & Pitfalls to Watch
Three-year lookback test: Many assume notification is only for first-time claimants. But if your last valid claim is more than three years prior to the end of the current notification window, you'll need to notify again.
Amended claims trap: If you amend a filed CT600 after 1 April 2023 to add an R&D claim for an earlier period, you may need to submit notification even if another claim was filed recently.
Strict timing: Late notification is generally not accepted. Missing the window risks the entire claim’s rejection.
Low-level detail expectations: HMRC guidance is minimal about the depth of description required in the notification. Many advisers recommend including a short project summary to avoid issues.
Notification does not replace the full claim: The CNF is preliminary. You still must submit the full R&D claim (and AIF) by standard tax return deadlines.
Examples
Example 1: First-time claimant
Company X has never claimed R&D before.
Its accounting period is 1 April 2024 to 31 March 2025.
It must notify HMRC via CNF by 30 September 2025, before filing the full claim.
Example 2: Last claim more than 3 years ago
Company Y last claimed in 2019.
It now intends to claim for year ending 31 December 2024.
Since more than three years have passed, it must submit CNF even though it’s not first-time.
Example 3: Amendment scenario
Company Z’s period was 1 October 2022–30 September 2023.
It filed no R&D claim then, but in June 2024 amends that period’s CT600 to include a claim.
Because that amendment occurs after 1 April 2023, CNF is required.
Conclusion
The Claim Notification (pre-notification) requirement is a procedural yet critical new hurdle. It forces companies to commit early, elevates transparency, and gives HMRC a filtering mechanism before full claims arrive.
Missing the notification window, or misapplying the exemption tests, risks invalidating what would otherwise be a valid R&D claim.
As always under the evolving regime, the key to staying ahead is knowing the rules, structuring early, and maintaining discipline over your claim timeline.