Two R&D tax relief developments have landed simultaneously this June, and both demand immediate attention from any CFO with an SME client or portfolio company that either claims — or is thinking about claiming — R&D relief. Miss the first and you lose the claim entirely. Ignore the second and you pass up a rare opportunity to get HMRC’s view on paper before committing to a position. Here is what you need to do, and when.
The June 30 Cliff Edge: R&D Claim Notification Form
Since April 1, 2023, any company claiming R&D relief for the first time — or that has not made a claim in the previous three accounting periods — must submit a Claim Notification Form (CNF) to HMRC before the claim itself is filed. The CNF must be submitted within six months of the end of the relevant accounting period. There is no grace, no late-filing relief, and no discretion: if the form is not in on time, the claim is void.
For companies with a December 31, 2025 year-end, that six-month window closes on June 30, 2026. That is four weeks away. If your company — or any company you advise — falls into this category and has not yet submitted the CNF, act now. Companies with a March 31, 2026 year-end have until September 30, 2026, but should not treat that as comfort: the window feels long until it doesn’t.
The notification is made through HMRC’s online service. It asks for basic company details and a brief description of the R&D activity — it is not the claim itself. But without it, the claim cannot proceed. Accountants at Hurst and PKF Francis Clark have both published warnings this week. Take them seriously.
Who the CNF Applies To — and the Common Misconception
The CNF requirement catches two groups: companies making their first-ever R&D claim, and companies that claimed previously but whose most recent claim was for an accounting period ending more than three years before the period now being claimed. A company that has claimed every year since 2020 does not need to notify. A company that claimed in 2021, had no qualifying expenditure in 2022–2024, and now wants to claim again for 2025 — it does.
The three-year look-back is measured from the last claim submitted, not the last period of R&D activity. This catches companies that paused their claims during the post-2023 reform uncertainty. If your client stopped claiming while the merged scheme and the new rules settled, and is now ready to re-engage, check whether the CNF window is still open before doing anything else. As TBAT Innovation and AAB both note, this is a hard stop — not a technical formality.
HMRC’s New Targeted Advance Assurance Pilot: What It Is
Separately, HMRC launched a new Targeted Advance Assurance (TAA) pilot on May 18, 2026, running until May 2027. It is available to SMEs — broadly, fewer than 500 employees and either turnover below €100 million or assets below €86 million — that have not yet submitted their R&D claim for the relevant period.
The pilot allows a company to seek HMRC’s view on up to two specific, high-risk areas of their claim before submitting it. The four areas currently in scope are:
- Whether a project meets the statutory definition of R&D for tax purposes
- Whether overseas expenditure on Externally Provided Workers or contracted R&D qualifies
- Whether R&D relief can be claimed where work is contracted from one company to another (the “contracted out R&D” rules)
- Whether the company qualifies for exemption from the PAYE/NIC cap
Applications are made online, covering company registration, senior officer contact details, and project information including forecasted expenditure and records held. HMRC commits to a 40-day response window, delivering its decision by letter with reasons. The Association of Taxation Technicians and ICAEW have both welcomed the pilot as a meaningful step forward in an otherwise compliance-heavy regime.
What the TAA Pilot Is Not — Managing Expectations
The TAA is targeted and narrow. Each application covers one project and one area; if you need assurance on two areas of the same project, that requires two separate applications. The existing Full Advance Assurance scheme — aimed at first-time SME claimants wanting whole-claim certainty — remains in place, but a company cannot use both for the same period.
Critically, if HMRC rejects the assurance application, there is no right of appeal and no ability to re-apply. HMRC’s rejection does not, however, prevent the company from filing the underlying claim. As KPMG UK note, the pilot is particularly valuable for companies within R&D supply chains, those with overseas expenditure, or those preparing for a transaction where certainty over R&D claims is a due diligence item. The 40-day window means it is a pre-transaction tool only if you build in the lead time — which most deal timetables do not naturally accommodate.
Why This Matters: The 2023 Reform Hangover
The introduction of the merged R&D scheme from April 2024 — combining the old SME and RDEC regimes — was accompanied by tightened rules on overseas expenditure and contracted-out R&D that remain poorly understood in practice. Many companies that were comfortable with the old regime have not yet fully mapped their activities to the new rules. That uncertainty is precisely what the TAA pilot is designed to address for the contracted-out R&D and overseas expenditure questions.
At the same time, HMRC has been running an aggressive compliance programme since 2023, targeting inflated and fraudulent R&D claims. The result is a regime that is simultaneously more generous in some respects — the merged scheme rate for profit-making companies improved — and more scrutinised. Getting a targeted assurance letter before claiming is not just about certainty; it is a risk management tool that demonstrates good faith if HMRC subsequently opens an enquiry.
CFO Action List for June 2026
- Identify all companies with December 31, 2025 year-ends that are eligible for R&D relief and have not previously claimed — or have not claimed within the past three periods. Check the CNF status immediately.
- Submit the CNF by June 30, 2026 for any company in scope. Do not conflate this with the actual R&D claim — the claim deadline follows the corporation tax return deadline, typically 12 months after year-end. The CNF is the prerequisite, not the claim.
- Assess TAA eligibility for any SME in a complex R&D position: overseas workers, supply chain R&D, or contracted-out arrangements. If the technical qualification is uncertain, a 40-day HMRC letter is worth considerably more than an adviser opinion in an enquiry context.
- Separate TAA from deal timelines. If a transaction is 90 days out and R&D claims are on the data room, the TAA process will not complete in time. In that scenario, instruct specialist R&D counsel for a technical opinion instead.
- Review the merged scheme rules if you have not already. The BDO guidance on R&D advance clearances and the HMRC manuals on overseas expenditure and contracted-out R&D are the starting points.
The Bottom Line
R&D tax relief remains one of the most valuable reliefs available to UK companies, but the compliance infrastructure around it has hardened considerably since 2023. The CNF is a bureaucratic requirement with a hard deadline and zero tolerance for lateness. The TAA pilot is an under-used opportunity to lock in HMRC’s position on the areas of the regime most likely to attract enquiry. Both deserve to be on every CFO’s June checklist.
If you are working through R&D relief eligibility for a December year-end company, or assessing whether the Targeted Advance Assurance pilot makes sense for a portfolio company, contact Mark Hendy at mark@tanous.co.uk or visit tanous.co.uk. Tanous provides PE-facing CFO advisory and tax compliance support — including R&D structuring and claim review — for owner-managed businesses and private equity-backed companies.