Definition
The Agent Services Account is a HMRC digital account held by the adviser firm, not by the client company. It sits alongside the older agent reference number system and gives access to a growing range of HMRC digital services. Advisers use it to manage client authorisations and to access services that have migrated away from the legacy agent portal.
For R&D tax relief specifically, the ASA is the route through which an adviser can be authorised to submit the Additional Information Form (AIF) and, in due course, interact with HMRC's digital R&D systems on the client's behalf. Companies authorise advisers by granting access through their own HMRC online account.
How the mandatory R&D agent registration changes things
The Autumn Budget 2024 announced that HMRC would introduce a register of R&D tax advisers. From 18 May 2026, any person or firm that acts for a company in relation to an R&D tax relief claim must be registered with HMRC. This applies regardless of whether the adviser is a qualified accountant, a specialist R&D consultancy, or an individual acting in a sole-trader capacity.
The ASA and the adviser registration are two separate things. An adviser may already hold an ASA but still need to complete the registration. HMRC's published guidance covers who must register and the timeline: check if and when you need to register as a tax adviser with HMRC.
The registration requirement is part of HMRC's broader effort to reduce error and fraud in R&D claims. HMRC estimated cumulative error and fraud in R&D relief at £4.1 billion in its 2024 publication, and the registration regime is one of several measures introduced since 2023 to tighten oversight of the adviser community.
Example
A small R&D specialist firm has been submitting R&D claims for manufacturing clients since 2019. Before the merged scheme launched in April 2024, the firm used the legacy agent portal. It has since set up an Agent Services Account to access HMRC's updated digital services. In May 2026, it completes the mandatory adviser registration. It can now continue to act for clients on R&D claims in full compliance with HMRC's requirements. A client that asks to see proof of registration can be directed to the firm's registration reference.
Common mistakes
The most common error is conflating the ASA with the adviser registration. Holding an ASA does not mean a firm has completed the May 2026 registration requirement. The two processes are separate and both are required for advisers acting on R&D claims after that date.
A second mistake is companies not asking their adviser whether they are registered. The registration regime exists partly to give companies a way to verify that the person handling their claim meets HMRC's requirements. Advisers who cannot confirm registration after 18 May 2026 are not compliant.
See the agent registration (HMRC) entry for a broader treatment of how agent registration works for R&D claims. For accountants who refer clients to R&D specialists, the for accountants page explains how Uplift Tax works with the accounting community. Use the eligibility checker if you want to assess a potential R&D claim before engaging a specialist.
Related terms
- Agent Registration (HMRC)
- Additional Information Form (AIF)
- Claim Notification Form
- Compliance Check
- Merged R&D Scheme
Frequently asked questions
What is an Agent Services Account?
An Agent Services Account (ASA) is the HMRC online account that tax advisers and accountants use to access HMRC's digital services on behalf of their clients. It replaces the older agent reference number system for services that have migrated to HMRC's digital infrastructure. For R&D tax relief, having an ASA is a prerequisite for submitting claims through HMRC's online services.
What is the mandatory R&D agent registration from 18 May 2026?
From 18 May 2026, any adviser who acts for a company on an R&D tax relief claim must register as an R&D tax adviser with HMRC. This is separate from obtaining an ASA, though both are now required. The registration was announced in the Autumn Budget 2024. HMRC's guidance is at www.gov.uk/guidance/check-if-and-when-you-need-to-register-as-a-tax-adviser-with-hmrc.
Does a company need an ASA itself?
No. The Agent Services Account is held by the adviser, not the company. The company authorises the adviser to act on its behalf through the relevant client authorisation process. The company's own HMRC online account (Government Gateway) remains separate.
How does a company know if its adviser is properly registered?
From 18 May 2026, companies can ask their adviser to confirm they have completed the mandatory R&D adviser registration. An unregistered adviser acting on an R&D claim after that date is not compliant with HMRC's requirements. Asking for confirmation of registration is a reasonable part of the adviser selection process.