Before the Budget on 28 October 2026, a company that missed its claim notification deadline had no prospect of making the R&D claim: there is no late route and no appeal, however genuine the work. The Budget announced that R&D claims made on or after 1 April 2027 will no longer need a notification, and HMRC’s manual now says this includes claims made by amending a company tax return.
If the legislation follows the announcement, some companies that missed their deadline may be able to make the claim after all. Not every company, though. The claim window for the year has to be open on 1 April 2027, and a claim that HMRC has already struck out is caught by a separate rule that nothing announced so far changes. And because the change is not yet law, a claim for a missed year should not be filed before 1 April 2027.
The rule today
A company that has not made an R&D claim in the three years ending with its notification deadline, which includes any first-time claimant, must either notify HMRC by that deadline or make the claim itself by then. The deadline is the last day of the six months beginning with the day after the period of account ends: a 31 March year end gives 30 September.
The rule bars a claim made after the deadline without a notification. HMRC’s manual says the legislation prevents “the making of a claim … after the end of the claim notification period”. Until the Budget, that meant the claim was lost for good.
What the Budget announced
The government will remove the requirement to notify “for R&D claims made on or after 1 April 2027”, by amending the Corporation Tax Act 2009 in Finance Bill 2026-27. HMRC updated its manual the next day: “For claims made on or after 1 April 2027, including claims made by amendment, the company will no longer be required to pre-notify HMRC of their intention to claim.”
The test is the date the claim is made, not the year it relates to. That is what opens the door. A company can make or amend an R&D claim up to two years after the end of its period of account (normally its financial year). So a claim for an earlier year, made by amended return on or after 1 April 2027 while that two-year window is still open, would fall outside the notification rule as announced.
This is our reading of the announcement and HMRC’s guidance. The Finance Bill clause has not been published, and it may include transitional rules for years whose notification deadline has already passed. Until the clause is published and enacted, this is a possibility rather than a certainty.
Which year ends could benefit
The two-year claim window has to be still open on 1 April 2027. For month-end year ends, that means years ending on or after 30 April 2025.
| Year ended | Notification deadline | Claim window closes | Position, if enacted as announced |
|---|---|---|---|
| 31 March 2025 or earlier | 30 September 2025 or earlier | 31 March 2027 or earlier | No second chance: the claim window closes before the change |
| 30 April to 30 September 2025 | 31 October 2025 to 31 March 2026 | 30 April to 30 September 2027 | May be claimable from 1 April 2027. These windows close first |
| 31 October 2025 to 30 April 2026 | 30 April to 31 October 2026 | 31 October 2027 to 30 April 2028 | May be claimable from 1 April 2027 |
| 31 May to 30 September 2026 | 30 November 2026 to 31 March 2027 | 31 May to 30 September 2028 | Deadline still ahead: we recommend notifying by it |
| 31 October 2026 onwards | 30 April 2027 or later | 31 October 2028 or later | Deadline falls after the change. We still recommend notifying until Royal Assent |
The dates assume a twelve-month period of account. A long or short period, or a change of year end, moves them.
A company with a 31 March 2025 year end misses by a day. Its claim window closes on 31 March 2027, the day before the change would take effect. HMRC accepts late claims only under its Statement of Practice 5/01, which should not be relied on to bridge the gap.
The exception: claims HMRC has already struck out
Where a company filed a claim without the notification it needed, HMRC can correct the return to strike the claim out. A separate rule then applies. Where the original claim needed a notification and none was made, “the company may not make a new claim … in respect of the expenditure to which the original claim related”, in the words of the Finance Act 1998.
That rule looks back at the original claim, which was made while a notification was required, so on its current wording the April 2027 change does not reopen it. The announcement does not mention it. Unless the Finance Bill changes it, a year that HMRC has struck out because no notification was made stays lost.
Don’t file a missed year now
A claim made today for a year whose notification deadline has passed is invalid under the current rules. If HMRC strikes it out, the rule above could shut that year off permanently, even after the change. The better course is to prepare the claim now, while the records and the people involved are to hand, and hold it until 1 April 2027 at the earliest, once the legislation confirms the position.
If a claim for a missed year is already in a return and HMRC has not yet acted on it, take advice before doing anything. The right step depends on the facts and on what the final legislation says.
Before you assume you missed it
Some companies that believe they missed the deadline did not need to notify at all. The notification was not required if:
- the company made an R&D claim in the three years ending with the notification deadline;
- the company tax return containing the claim reached HMRC by the notification deadline; or
- the company notified, or claimed, for another accounting period in the same period of account.
Two kinds of earlier claim don’t count towards the three years: a claim HMRC struck out, and a claim made by amendment on or after 1 April 2023 for an accounting period that began before that date. Our claim notification checker works out the deadline and tests the three-year exemption.
If your deadline is still ahead
We recommend notifying. A company with a 31 May 2026 year end has until 30 November 2026, and one with a 30 September 2026 year end has until 31 March 2027. The change is announced but not enacted, and a notification costs nothing beyond the form. That recommendation holds for every deadline until the legislation has Royal Assent.
Matthew Jones, Managing Director of LimestoneGrey, said:
“We have had to tell companies that a year of genuine R&D could not be claimed because a form was missed. For some of them, this announcement may change that. It will not help everyone, and it is not law yet, so no one should write a missed year off without checking it, or rush a claim in before April.”
What to do now
- Check the year end against the table above.
- If a missed year could benefit, gather the R&D records and costs now, but don’t file before 1 April 2027.
- If HMRC has already struck out a claim, or a claim without a notification is sitting in a return, talk to an adviser before acting.
- If a deadline is still ahead, we recommend notifying.
We will update this article when the Finance Bill clause is published.
Sources
- Budget 2026: overview of tax legislation and rates, HM Treasury, 28 October 2026, section 1.47: legislation in Finance Bill 2026-27 to remove the Claim Notification Form “for R&D claims made on or after 1 April 2027”.
- Research and Development (R&D) tax reliefs: improving the customer experience, HMRC tax information and impact note, 28 October 2026: the change to be made by amending the Corporation Tax Act 2009.
- HMRC manual, CIRD183000 and CIRD181000, updated 29 October 2026: claims made on or after 1 April 2027, “including claims made by amendment”; the notification bar and its exceptions; late claims accepted only under Statement of Practice 5/01.
- Corporation Tax Act 2009, section 1142A: the claim notification period ends with the last day of the six months beginning with the day after the period of account ends.
- Corporation Tax Act 2009, sections 1042C and 1045A: the bar on merged-scheme and ERIS claims made after the notification period, and its three exceptions.
- Finance Act 1998, Schedule 18, paragraph 83E (the two-year claim window), paragraph 83EB (claims HMRC strikes out, and the bar on a new claim for the same expenditure) and paragraph 16 (HMRC’s power to correct a return).
Every CIRD paragraph cited above (CIRD181000 and CIRD183000) is indexed on our CIRD reference index, with HMRC’s own title for each, a line on what it says and the date HMRC last revised it.
This article describes the rules as they stood at the review date above. The rules change: for the current position, start with our guides or talk to us.
