Mandatory R&D Agent Registration from 18 May 2026: What to Ask Your Advisor

HMRC's mandatory adviser registration scheme requires any business that is paid to interact with HMRC on behalf of a client to register through a new online system. The first registration deadline was 18 May 2026, taking effect under legislation in the Finance Act 2026. An unregistered adviser cannot legally file returns, submit claim forms, or contact HMRC on your behalf. For an SME in the middle of an R&D tax claim, that is a practical problem that can stall a refund. This page sets out what the scheme means, how to check your adviser's position, and what questions to ask.

What Changed and Why

Before May 2026, there was no formal register of tax advisers in the UK. Any individual or company could set themselves up as an R&D tax specialist without any oversight. The consequences were visible in HMRC's compliance reports: a large proportion of R&D claims contained errors or overclaims, and a minority involved fraud. HMRC's own data showed that in 2021 to 2022, around 30 per cent of SME R&D claims were wholly non-compliant.

Mandatory registration is one part of a package of measures to raise standards. The others include the Additional Information Form introduced in August 2023, the named officer requirement on that form, and the Mandatory Random Enquiry Programme. Together, they are designed to make it considerably harder for poor-quality advisers to operate without accountability.

The gov.uk guidance on registration describes the requirement simply: if you interact with HMRC about someone else's tax affairs and you are paid to do so, you must register. This applies whether or not tax advice is your main business and whether or not you act for only one client.

Who Must Register

The registration requirement is broad. It covers any organisation or individual that interacts with HMRC on a client's behalf and receives payment for it. Interaction means:

• Sending returns, claims, or other documents (including the R&D Additional Information Form)
• Contacting HMRC by phone, post, or email
• Sending messages through the GOV.UK website or HMRC app

This captures R&D-only boutique firms, general practice accountancy firms that handle R&D as part of their service, outsourced tax advisers, and any agent with an Agent Services Account who submits claims. Registration is at the legal entity level, not the individual. A sole trader R&D consultant registers under their own name. A partnership registers as the firm.

Who Does Not Need to Register

Several groups are exempt:

• In-house tax teams advising only their own employer (no client relationship)
• Individuals or organisations providing purely free, pro-bono advice
• Insolvency practitioners acting in that capacity
• Payroll software providers whose only role is submitting payroll data on a client's behalf
• Financial services firms regulated by the FCA (window opens 31 December 2026; full compliance deadline currently 31 March 2027 pending legislative refinement)

A general practice accountant that does any paid tax work beyond payroll must register. The exemption for payroll-only providers is narrow.

Registration Deadlines

HMRC has staggered the deadlines by the type of adviser:

Each group has a three-month window from its deadline to apply. Advisers can continue interacting with HMRC during the application window while HMRC considers their registration. The full rollout is expected to complete by 31 March 2027. Early registration was permitted from 18 May 2026 for any group, so a well-organised adviser should already be registered or have applied.

The Three Conditions for Registration

To register, a firm must confirm three conditions. These are not a one-time declaration; HMRC expects ongoing compliance. If a registered firm ceases to meet any condition, it must notify HMRC.

Condition 1: Clean tax and compliance record

The firm must have no outstanding tax returns or tax payments owed to HMRC, no director disqualification in the past five years, and no relevant anti-avoidance penalties or criminal convictions. This condition is designed to exclude advisers who do not comply with their own tax obligations from acting for others.

Condition 2: Anti-Money Laundering supervision

The firm must be registered with an approved Anti-Money Laundering supervisory body. For accountancy firms, this is typically HMRC itself (for smaller practices) or one of the professional body supervisors such as the ICAEW, ACCA, or CIOT. Standalone R&D boutiques that are not members of a professional body and have not registered for AML supervision face a practical difficulty here, because they must first obtain AML supervision before they can meet this condition.

Condition 3: Relevant individuals named

The firm must identify the individuals who direct or manage its tax work. For firms with five or fewer officers, all officers must be named, plus any employees who substantially direct tax activities. For larger firms, those managing tax work must be named, and enough additional officers named to reach a minimum of five. This creates personal accountability at senior level within the firm.

What an Unregistered Agent Cannot Do

Once an adviser's registration deadline passes and they have not registered (or applied), they cannot legally interact with HMRC on a client's behalf. In practical terms for an R&D claim:

• They cannot submit the Additional Information Form on the company's behalf
• They cannot file the Corporation Tax return (CT600) that contains the R&D claim
• They cannot respond to HMRC enquiry letters or questions about the claim
• They cannot call HMRC to discuss the client's position

An adviser who continues to attempt HMRC interaction after their deadline without having applied for registration risks escalating penalties: an initial compliance notice, then financial penalties for the firm and for named individuals, and ultimately a potential ban from re-registering. The client company is not directly penalised for using an unregistered adviser, but the practical consequences are serious: claims may stall, enquiries may go unanswered, and refunds may be delayed.

Questions to Ask Your R&D Adviser Right Now

If you have an R&D adviser handling your claim, ask them the following directly. A reputable firm will answer without hesitation. Vague or evasive answers are a signal to probe further or seek a second opinion.

Question 1: Have you registered with HMRC, or submitted your registration application?

This is the first thing to confirm. Ask for the firm name as it appears on the HMRC register, or ask to see confirmation of a pending application. Given that registration opened on 18 May 2026, any firm that has not yet registered or applied is behind. Ask when they expect approval.

Question 2: What is your AML supervision body?

AML registration is a condition for HMRC registration. The adviser should be able to name their supervisory body immediately. Common answers are HMRC (for small firms under the government's own AML supervision regime), ICAEW, ACCA, CIOT, or ATT. If the adviser cannot answer this question, that is a concern about their underlying compliance, not just their HMRC registration status.

Question 3: Who in your firm is the named relevant individual for HMRC purposes?

The registration requires the firm to name the individuals who manage its tax work. Ask who those people are and confirm they are still with the firm. This matters because the named individuals carry personal accountability. If the relevant individuals have left and the registration has not been updated, the firm may be in breach.

Question 4: What is your complaint and oversight process?

Registered advisers must meet conditions including professional body membership or AML supervision. This gives a client a route of complaint that did not previously exist for unaffiliated boutique R&D firms. Ask what body to contact if there is a dispute.

Question 5: What happens to my claim if your registration is delayed?

During the three-month application window, an adviser can continue to interact with HMRC. But if there are delays and the window closes before approval, the adviser loses the right to act. Ask the firm how they would manage continuity in that scenario.

What This Means for Claim Quality

Mandatory registration is partly about accountability and partly about raising the floor on adviser quality. By requiring AML supervision and a clean tax record, and by naming individuals who are personally responsible, the scheme makes it harder for firms with poor practices to continue. It does not guarantee that a registered adviser produces quality claims, but it creates a framework for oversight that did not previously exist.

The parallel changes to PCRT standards from January 2026 add another layer: professional body members must comply with updated conduct standards that affect how they handle R&D claims specifically. Together, registration and PCRT mean the bar for being an R&D adviser has risen materially in 2026.

For companies choosing an adviser, this creates a practical checklist. An adviser who is registered, AML-supervised, a member of CIOT or ICAEW, and operates under PCRT is operating within a framework of accountability. An adviser who cannot confirm those points is not.

Uplift Tax introduces companies to specialists who meet these standards. See how our introduction process works, or request a free assessment if you want to check whether your current adviser's registration is in order before your next claim.