R&D claim notification form requirement to end in April 2027 

The Autumn Budget brought welcome news for prospective R&D tax relief claimants: the R&D claim notification form (CNF) requirement will be removed for claims made on or after 1 April 2027. This creates an opportunity for some companies that missed the CNF filing deadline to make a claim retrospectively.

The change follows feedback that the requirement places an additional administrative burden on innovative companies, which can lose out on tax relief simply by missing a fixed deadline.

What is an R&D claim notification form? 

The CNF requirement was introduced as part of a package of measures aimed at reducing error and fraud within the R&D tax relief schemes. 

In broad terms, companies must notify HMRC in advance if they plan to claim R&D tax relief for the first time, or for the first time in more than three years. The form must be submitted within six months of the end of the relevant period of account. Failure to submit means the company loses the opportunity to claim R&D tax relief for that period. 

What is changing? 

Following the Autumn Budget, the government confirmed that the requirement to submit a CNF will be removed for R&D claims made on or after 1 April 2027. 

The change forms part of a wider simplification of the administration of R&D tax relief, including the planned simplification of the Additional Information Form (AIF) from autumn 2027.

Importantly, the change is based on the date the R&D claim is made, rather than the start or end date of the relevant accounting period.

Could companies that missed the CNF deadline still claim? 

Companies that undertook qualifying R&D, were required to submit a CNF but missed the six-month deadline, and which remain within the normal R&D claim filing window after 1 April 2027 may have another opportunity to claim. This could apply to any company that undertook qualifying R&D but missed the CNF deadline for a period ending after 1 April 2025.

For example, a company with a 30 April 2025 year end that undertook qualifying R&D but missed its CNF deadline on 31 October 2025 has lost its opportunity to claim under the current rules.

However, the company’s normal deadline for making an R&D claim is 30 April 2027, in line with the two-year amendment window for Corporation Tax returns. This means there will be a window between 1 April and 30 April 2027 during which the company can make its R&D claim, even though it missed the CNF deadline.

It is worth noting that removing the CNF requirement will not make valid a claim that was previously submitted without the required CNF. Instead, a new claim may be made from 1 April 2027, provided that its statutory submission deadline falls after that date. The other requirements for a valid R&D claim will still apply.

What should companies do now? 

Companies that previously identified qualifying R&D but were unable to claim because they missed the CNF deadline should review their position if they have a relevant period of account ending after 1 April 2025.

The closer the year end is to 1 April 2025, the shorter the available claim window will be. Companies in this position should therefore consider their circumstances well in advance, rather than waiting until April 2027. This will allow any potential claim to be submitted promptly once the CNF requirement is removed.

Removing the CNF requirement will not affect the other requirements associated with making an R&D claim. Companies will still need to demonstrate that their activities qualify for R&D tax relief, calculate the qualifying expenditure correctly and submit the required Additional Information Form alongside the claim.

Next steps 

If your company undertook qualifying R&D but missed the CNF deadline, now is the time to review whether the removal of the requirement could create another opportunity to claim. The available window may be short, so preparing well before April 2027 will be important.

Contact our R&D tax relief team to discuss the relevant accounting period, confirm the applicable deadlines and assess whether your company may be able to submit a claim from 1 April 2027.