Tax advisers who interact with HMRC on behalf of clients are now required to register with HMRC, with anti-money-laundering supervision a condition of registration. For companies claiming R&D tax relief, the direction of travel is unmistakable: an accountable advice market, where the standards a firm works to matter as much as the claims it files. Choosing a regulated, chartered adviser is no longer a preference. It is risk management.
Why has scrutiny of R&D advice increased?
Because the market earned it. HMRC significantly tightened its compliance response to error, abuse and poor-quality advice in R&D claims, and the results are visible in the data: error and fraud fell from 17.6% in 2021-22 to a measured 6.4% in 2023-24, with HMRC estimating 5.3% for the two years since. Claims are now expected to be detailed, evidenced and clearly mapped to the definition of qualifying R&D. The Additional Information Form forces every claim to state the advance sought, the uncertainties faced, the work done and the costs claimed in a structured way.
For deep tech companies this raises the technical bar as well as the administrative one. In life sciences and biotech, a claim must do more than describe an innovative product: it must explain why the scientific challenge could not readily be solved by competent professionals in the field.
What is changing for advisers?
Registration with HMRC is now mandatory for tax advisers who deal with HMRC on clients’ behalf, and AML supervision is a condition of registering. Alongside it, HMRC published a non-binding online checker in September 2025 that lets companies test whether their activity is likely to qualify before anyone files anything.
The practical question for a claimant is simple. Do you want an adviser who has operated to professional standards all along, or one scrambling to meet a minimum threshold as the market catches up?
What does an unregulated adviser actually cost you?
Poorly prepared claims and bad advice convert directly into HMRC enquiries, delayed repayments, penalties, amended returns and management time you do not get back. The damage also travels: historic claims that cannot be supported surface during investment due diligence, grant applications and acquisitions, at exactly the moment a company can least afford doubt about its numbers.
Regulation is the counterweight. A firm regulated by a chartered body is bound by Professional Conduct in Relation to Taxation, carries professional accountability for its work and answers to a complaints route that exists independently of the firm. We set out what that means in practice, for clients rather than for us, on our regulation and standards page.
What is LimestoneGrey’s position?
Matthew Jones: “For innovation-led companies, regulation should not be seen as a barrier to claiming. It should be seen as a mechanism to claim properly.
LimestoneGrey has been regulated since our inception because we believed from the outset that companies deserve more than transactional R&D tax advice. They deserve support from a firm operating to recognised professional standards, with accountability, technical competence and care built into the process. We are not playing catch-up as the market changes, we have always believed this is the standard businesses should expect.
Companies in deep tech sectors are often carrying out exactly the kind of work the R&D tax relief regime was designed to support. But in a higher-scrutiny environment, claims need to be accurate, evidence-led and professionally prepared. This is why choosing the right adviser is now a key part of protecting your business.”
LimestoneGrey approaches R&D tax relief as a professional tax matter, not a funding exercise: identifying genuine qualifying R&D, gathering the right evidence, preparing narratives that stand up to scrutiny, and standing behind the claims we prepare as standard. You can read more about the chartered adviser who leads that work on Matthew’s profile.
If you are reviewing who prepares your claims, start a conversation with a chartered adviser.
Sources
- Tax advisers to register with HMRC — mandatory adviser registration and minimum standards from May 2026.
- HMRC’s approach to R&D tax reliefs 2023–24 — 17% of claims checked, 500-plus compliance staff and estimated error and fraud of 17.6%.
- HMRC annual report and accounts 2025–26 — error and fraud measured at 6.4% for 2023-24, with 5.3% estimated for the two years since.
- Check if a project qualifies as R&D (checker) — HMRC’s non-binding online qualification checker.
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.
