A company claiming R&D relief for the first time, or for the first time in three years, must send HMRC a claim notification form within six months of the end of its period of account. For most companies that deadline falls before the accounts are finished.
If a notification was needed and none was sent, the claim for that period is invalid, even if the work qualifies as R&D.
What the claim notification form is
For accounting periods starting on or after 1 April 2023, a company must tell HMRC in advance, using a separate online form, that it intends to make an R&D claim if either of these applies:
- It is claiming for the first time.
- Its most recent claim was made more than three years before the last day of this period's notification window.
The three years are measured from the date the earlier claim was made, whichever period it covered. Two kinds of earlier claim do not count: a claim HMRC removed from a return, and a claim for a period beginning before 1 April 2023 that was added by amending a return on or after 1 April 2023. If the company made a claim that does count within the three-year window, no notification is needed and you claim on the return as before.
The deadline
The notification window starts on the first day of the period of account, the period covered by the company's accounts, and ends 6 months after that period ends. The Company Tax Return is due 12 months after the end of the accounting period, and a claim can be made or amended up to 24 months after it, so the notification deadline often passes before a company starts work on the claim. Where a period of account is longer than 12 months, the six months run from the end of the whole period of account.
Worked example: a first claim that missed the notification deadline
The figures below are illustrative. A software company has a 31 March 2026 year end. It has traded since 2022 and has never claimed R&D relief, because the founders thought it applied only to laboratories and universities. In the year to 31 March 2026 it spent £180,000 on qualifying staff costs, subcontracted development and software for technical work that involved genuine uncertainty.
Because this would be a first claim, notification was required by 30 September 2026. The founders first raise it with their accountant in mid-November, while preparing papers for the January board meeting, about six weeks after the deadline.
The claim notification and the Additional Information Form
The Additional Information Form (AIF) is a separate form, and the two are often confused. The AIF is required for every R&D claim, first-time or not, and sets out the detail behind the claim: the qualifying costs, the projects and the technical uncertainties addressed. It must be sent before, or on the same day as, the Company Tax Return that contains the claim.
The claim notification is a shorter form, needed only where the company has not claimed in the last three years, and due six months after the end of the period of account. A missed notification cannot be put right for that period. A missing Additional Information Form also makes the claim invalid, but the company can send the form and make the claim again by amending the return, as long as the time limit for amending it has not passed.
What the form asks for
It is a short online form and does not ask for evidence of the R&D. You will need:
- The company's Unique Taxpayer Reference.
- The start and end dates of the accounting period and of the period of account.
- Contact details for the main senior internal R&D contact, and for every agent involved in the claim.
- A summary of the high-level planned R&D activities.
Loss-making R&D-intensive companies
If your company is a loss-making small or medium-sized enterprise (SME) and its qualifying R&D spending is at least 30% of its total relevant expenditure, it can claim Enhanced R&D Intensive Support (ERIS) instead of the merged scheme. ERIS gives an extra 86% deduction (186% in total) and a payable credit of 14.5% of the loss surrendered, capped at £20,000 plus 300% of the company's PAYE and National Insurance. The notification rules apply to ERIS claims in the same way, so a missed notification means that credit cannot be claimed for the period.
What to do this week
- Find the end date of the period of account you plan to claim for, and count forward six months to find your notification deadline, if a notification is needed.
- Check the date the company last made an R&D claim. If it made one in the three years before this period's notification deadline, no notification is needed, unless that claim was removed by HMRC or was a late amendment for a period before April 2023.
- If you have never claimed, or your last claim was more than three years before this period's notification deadline, put the notification deadline in the diary now.
- If your company is loss-making and spends heavily on R&D, check whether it meets the 30% threshold for ERIS. Both routes need the same notification.
- If a notification was needed for a period and the deadline has passed, the claim for that period cannot be made. Make sure the next period is notified on time.
Whether your work qualifies as R&D is decided by the government's R&D guidelines, which were updated for periods beginning on or after 1 April 2023 to include advances in mathematics. The notification rules decide whether a claim can be made. Our post on R&D tax relief for startups covers what qualifies and how the merged scheme is calculated, and our guide to corporation tax for startups covers how the credit fits with the rest of your corporation tax.
Where we help
We track your accounting period end, flag the notification deadline as soon as the window opens, and send the notification, where one is needed, and the Additional Information Form for every claim we prepare. R&D claims are a fixed fee that includes any HMRC enquiry, and your monthly accounting fee comes from the instant quote. Get started.
