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Further information (part 6)

Updated 23 January 2025

Amending your company tax return

You can amend your tax return to make, amend or withdraw your claim:

For periods of account ending before 1 April 2023:

• within 12 months of the statutory filing date

For periods of account ending after 31 March 2023:

• within the 2 years beginning with the last day of a period of account up to 18 months in length
• within the 42 months beginning from the first day of the period of account in any other case

More information about claims and time limits

If you can no longer amend your tax return

If you have claimed more R&D tax credits or reliefs than you should in a period, then use the R&D disclosure service to give HMRC the details.

If you have claimed less R&D tax credits or reliefs than you could in a period, then you may ask HMRC to consider accepting a late claim to credit or relief. All late claims should include the necessary information and supporting computations, and necessary documents. This includes the content usually required on the additional information form. Requests to consider accepting late claims will be considered in line with Statement of practice 5 (2001).

Large Business customers who wish to make a late claim should refer to the section Time limits and claims — Large Business practice note, and contact your customer compliance manager (CCM).

Other customers who wish to make a late claim should send their claim, supporting computations and relevant documents to RD.IncentivesReliefs@hmrc.gov.uk, the email subject line should be marked ‘LATE CLAIM’. 

Other concerns 

If you have concerns about a claim you have made that are not answered after reading these guidelines and the linked material:

• email your  customer compliance manager
• email RD.IncentivesReliefs@hmrc.gov.uk if you do not have a CCM

For all emails

You should include the reference GFC3/2023 and copy in ccgguidelinesforcompliance@hmrc.gov.uk.

Sending information by email carries certain risks and HMRC will assume that by sending information by email you understand and accept these risks.

Guidance

We have designed these Guidelines for Compliance to give you an understanding of some of the main conditions for claiming research and development tax relief. But this is a complex area and there is more to understand before making a claim. This includes further important definitions in the Department for Science, Innovation and Technology (DSIT) guidelines. For further guidance, read:

• HMRC guidance on research and development tax relief

• HMRC detailed guidance on Research and Development tax relief

• Common errors in R&D claims

• The DSIT guidelines on the meaning of research and development for tax purposes

Where customers fail to meet their obligations, they may be subject to:

• penalties
• interest
• both penalties and interest

Read the HMRC compliance factsheets on penalties to find out more.