How far back can I claim R&D tax credits? - R&D tax deadline

You have two years from the end of your accounting period to submit an R&D claim for qualifying expenditure incurred in that period (but see claim notification requirements below if you haven’t claimed recently or are claiming for the first time).

The two year limit arises because R&D tax credits are a Corporation Tax relief claimed via your Corporation Tax return. You have 12 months from the end of your accounting period to submit your Corporation Tax return, and a further 12 months to amend it, resulting in a window of up to two years to submit your R&D claim.

What if I haven’t claimed recently or am claiming for the first time?

If you haven’t claimed recently or are claiming for the first time, then you may be required to let HMRC know that you intend to file an R&D claim. This is known as claim notification and is actioned via a form.

The requirements for pre-notifying HMRC only apply to accounting periods beginning on or after 1 April 2023. You must let HMRC know that you intend to make an R&D claim within six months of the end of the accounting period you wish to claim for (the claim notification period). For example, a company with a 31 March 2024 year end would need to pre-notify HMRC between 1 April 2023 and 30 September 2024.

You do not need to notify HMRC if you have made a previous R&D claim in the three years ending with the last day of the notification period for the relevant accounting period. So for the company above, the last day of the notification period is 30 September 2024, and three years prior to this is 1 October 2021. So, if an R&D claim for an earlier period had been filed between these dates, no notification should be required for the 2024 period.

There are transitional provisions covering the commencement of the notification rules which mean the company could still need to notify HMRC. If the previous claim was made in an amendment to a return and submitted after 1 April 2023, it is ignored for the purposes of the three-year window.  

Once you have notified HMRC, the usual two-year window for submitting your claim applies. For example, if the same company as above with a 31 March 2024 year end pre-notifies HMRC by 30 September 2024 that it intends to submit an R&D claim, then it has until 31 March 2026 to submit the claim.

You or your agent should notify HMRC of your intention to claim via a dedicated claim notification form. You will also need to confirm on your tax return for the relevant period that pre-notification has been completed, if applicable.

Long and short accounting periods

For the purposes of making an R&D tax credit claim, regardless of the length of your accounting period, the deadline for filing your claim will still be two years from the end of each accounting period.

Likewise if you are required to pre-notify, the deadline to do so will be six months from the end of the accounting period.

The rules are similar if you change your accounting period end date.

R&D claims outside the two-year range

HMRC does, in certain situations, have powers to allow the extension of the two-year time limit. These exceptions are, however, very rare and do not include a lack of awareness of the potential to make a claim for relief.

HMRC may waive the two-year limit in situations where “claims which could not have been made within the statutory time limits for reasons beyond the company’s control”. In its Statement of Practice SP 05/01, HMRC defines “reasons beyond the company’s control” as those where all of the following are present:

• An officer of the company was ill or otherwise absent for good reason.
• The absence or illness arose at a critical time and prevented the making of a claim within the normal time limit.
• There was good reason why the claim was not made before the time of the absence or illness.
• There was no other person who could have made the claim on the company’s behalf within the normal time limit.

In addition, a late claim may be accepted if at the time of the statutory filing deadline there was uncertainty regarding the amount of profit or loss, for example because of an open enquiry.

ForrestBrown specialises in helping companies navigate the R&D tax incentives: including both SME and RDEC. Our team of chartered tax advisers use their expertise to help innovative companies optimise their R&D tax credit claims and ensure all your qualifying activities and costs are properly identified.