R&D Tax Claim Notification: What the New Rules Mean for You

WHAT IS THE NEW R&D TAX CLAIM NOTIFICATION RULE?

If your company is planning to claim R&D tax relief, the R&D tax claim notification rule is something you need to know about. Introduced in April 2023, this rule means some businesses must notify HMRC before they submit a claim. Why is this so important? Because if you miss the deadline, you could lose the relief for that accounting period altogether.

WHO NEEDS TO SUBMIT AN R&D TAX CLAIM NOTIFICATION?

The rules mainly target “new claimants”, – but the definition is broader than you might expect. If your company hasn’t claimed R&D tax relief in the past three years, or if it’s your first time claiming, you’ll likely need to submit an R&D tax claim notification.

This applies to all companies with accounting periods starting on or after 1 April 2023. So even if you’ve claimed before, it’s worth checking your status. A notification is required if your company is:

• Making its first-ever claim, or
• Hasn’t submitted a claim within the last three years (counting back from the end of the relevant notification period).

WHEN DO YOU NEED TO MAKE AN R&D PRE-NOTIFICATION?

You’ll need to notify HMRC within the relevant “notification period” – this starts on the first day of your accounting period and ends six months after it finishes.

Examples:

• Year ended 31 December 2025
  • Notification period: 1 January to 30 June 2026
  • Deadline: 30 June 2026
• Year ended 31 March 2026
  • Notification period: 1 April to 30 September 2026
  • Deadline: 30 September 2026

EXCLUDED CLAIMS – A COMMON MISTAKE

Not all historic claims count towards the three-year lookback. This can catch companies out.

If your R&D claim was:

• Filed on or after 1 April 2023,
• Related to an accounting period that began before 1 April 2023, and
• Submitted as an amendment to a previous return –

…it won’t count towards your three-year history. That means you may still need to submit an R&D tax claim notification, even if you’ve made claims in the past.

Also, if you’re preparing claims for multiple years at once, you could be caught twice. We recommend checking every year.

CAN I STILL CLAIM R&D TAX RELIEF WITHOUT PRE-NOTIFICATION?

Yes, but only if you file your R&D claim within six months of the end of the accounting period.

R&D CLAIM FILING TIME LIMITS – REMAIN UNCHANGED

You still have two years from the end of your accounting period to submit an R&D claim. That hasn’t changed.

WHAT THE 2024 HMRC CHANGES MEAN FOR YOU

The 2024 reforms introduced a merged scheme for accounting periods starting after 1 April 2024. For some companies, this opens up new eligibility to claim R&D tax relief. A key change involves who can claim for work done under contract. Now, it’s usually the customer – the one commissioning the R&D – who can claim. That could mean you’re eligible when you weren’t before.

If this change affects you, you may need to submit an R&D tax claim notification to secure your claim. It’s crucial to review this early.

WHAT INFORMATION IS NEEDED TO NOTIFY HMRC OF AN R&D CLAIM?

To file an R&D tax claim notification, you’ll need:

• Your Unique Taxpayer Reference
• Contact details for the senior person responsible for the claim
• Details of any agents involved
• The start and end dates of the accounting period
• A summary of your planned R&D activities – including what you’re trying to achieve

KEY TAKEAWAYS

• Miss the notification deadline and you could lose your R&D tax relief for that year – permanently.
• Check your R&D tax claim notification requirement for every accounting period.
• Review your eligibility under the new merged scheme.

At AAB, we combine deep technical expertise with a commercial mindset to deliver robust, value-driven R&D tax solutions. With a proven track record across a wide range of sectors and a strong focus on compliance, we help businesses make the most of their innovation activity. Our experienced, multi-disciplined team includes both engineers and accountants, working together to ensure every claim is thorough, accurate, and successful. Our engineers identify qualifying projects and build the technical case, while our accountants handle the financial details. This joined-up approach gives you the technical expertise of engineers and the financial acumen of accountants. Delivering peace of mind, reduced risk, and help securing the full benefit you’re entitled to. We’re committed to guiding clients through the R&D tax process with clarity, confidence, and measurable results at every step.

If you have any queries about the changes to R&D tax claims or making a claim, please do not hesitate to get in contact with Ross Parsler or your usual AAB contact.