R&D Advance Assurance
Written and reviewed by the R&D Tax Accountants editorial team. Last reviewed 8 August 2026.
Advance assurance is HMRC agreeing the position before a claim is made rather than after. It is voluntary and free to apply for, and for the small group of companies that qualify it removes most of the risk from the early claims.
This page is what assurance is and who can get it. Preparing and submitting an application is on the advance assurance applications service page.
The Two Advance Assurance Routes
Full claim advance assurance is the original service. It applies to a company's first three accounting periods, and where HMRC agrees it sends a letter setting out the company's responsibilities. HMRC may follow up after the first claim to check it matches what the application described.
Alongside it there is a targeted route, run as a pilot, giving assurance on up to two specific complex or high-risk areas of a claim rather than on the claim as a whole. It suits a company that has a settled view of most of its position but one or two points it would rather not argue about after the fact.
The two are different products rather than tiers. Full assurance is broad and restricted to first-time claimants; targeted assurance is narrow and not limited in the same way.
Eligibility for Full Claim Assurance
The conditions are narrow. The company has to be a small or medium-sized enterprise, this has to be its first claim for R&D tax relief, turnover has to be below £2 million and it has to have fewer than 50 employees. Where the company is part of a group, no linked company can have claimed R&D relief before.
Those thresholds are much tighter than the general SME definition used for the relief itself, which allows up to 500 staff and turnover under 100 million euros. A company can comfortably be an SME for SME relief purposes and nowhere near eligible for advance assurance.
The group condition is the one that surprises people. A first claim by this company is not enough if a linked company has claimed before, which rules out most subsidiaries of established groups.
What Assurance Does and Does Not Cover
Assurance is agreement on the basis described in the application. It is not a blanket approval of whatever the company later files. HMRC may contact the company after the first claim to confirm the claim aligns with the application, and a claim that departs from what was described is not covered by what was agreed.
That matters most where a company's R&D moves on, which it usually does. A programme that has changed direction since the application is a reason to talk to HMRC rather than to assume the letter still covers it.
Assurance also does not remove the procedural requirements. An additional information form is still needed for every claim, and a first claim still needs a claim notification form within its window. Agreement on the technical position does not make a late notification valid.
When Assurance Is Worth Applying For
The obvious case is a company that qualifies, is planning R&D, and wants certainty before it commits. The less obvious case is that the application itself is useful. It forces the company to articulate its technological uncertainty and its record-keeping at the start of the programme rather than two years later, which is exactly the discipline that makes the first three claims defensible whether or not assurance is granted.
Where a company does not qualify, the effort belongs in the first claim instead, and the evidence base for a strong claim is the same evidence base an application would have needed. HMRC sets out the conditions and the process for full claim advance assurance, and companies at this stage are often applying for grant funding in parallel through Innovate UK.