HMRC publish updated guidance for Tax Adviser Registration regime

Examples for complex structures

The updated guidance within MTAR10200 now sets out 13 examples of how the registration requirement applies (or does not apply) to various types of organisational structure. The examples have been summarised below; however, potentially affected organisations and individuals should examine the detailed guidance in full:

Joint ventures (JVs)

1. Majority owned JV – in-house tax support for a JV more than 50 percent owned by the organisation is treated as exempt under the ‘group undertaking’ exemption (as set out by para 1(1)(f) of Schedule 20 Finance Act 2026 (FA 2026));

2. JV: 50 percent or less ownership – where the organisation manages the JV’s tax affairs but owns 50 percent or less, HMRC accept that the relationship is akin to in-house group support (and therefore treated as exempt);

3. JV partnership – one partner giving tax support to another partner on partnership tax matters is treated as similar to in-house group support;

4. Shareholder investments – an in-house tax team supporting shareholders on related UK investments may be treated as arising from ownership (and therefore treated as exempt);

Post-sale and transitional support

5. Pre-sale periods – post-sale tax services for former group companies do not require registration where they relate to periods before the sale;

6. Tax team sold with business – a tax team acquired by the buyer may provide time-limited transitional support back to the seller without registration;

7. Former JV investor – a former JV investor continuing tax-related services temporarily is treated as a transitional support case;

8. Sold business transition – time-limited tax support for a sold business while it moves to the buyer’s systems does not require registration;

Partnership and in-house compliance

9. Partnership tax affairs – a partner dealing only with the partnership’s tax affairs is treated as providing in-house type support, including for JV partnerships;

10. LLP and members – an LLP in-house team filing partnership and members’ tax returns is treated as part of wider in-house services;

11. Employee assignments – employer tax support for internationally mobile employees is treated as wider in-house activity;

Investment structures and SPVs

12. Funds and investors – fund manager or investment adviser tax support to fund entities, investees and investors is treated as in-house activity where part of the mandate; and

13. Orphan SPV – tax support for an orphan SPV by the sponsoring organisation is treated as similar to parent group in-house support.

The guidance states that the above examples are non-exhaustive and that the exemptions contained in Schedule 20 of FA 2026 should, in time, be expanded to cover these examples.

Potentially affected organisations and individuals should examine the details of the examples in the guidance in detail and check their circumstances against the final facts, who interacts with HMRC, and whether the relationship is genuinely third-party advisory.

Helpfully, MTAR10200 now also includes a statement that HMRC will not apply sanctions or penalties to organisations for a failure to comply where they have acted in good faith in relying on the guidance to determine that they should not register. 

Arrangements involving multiple businesses

MTAR10150 was also updated on 18 August 2026 to set out how the registration requirement applies in cases where tax advice is delivered through arrangements involving multiple businesses. The four examples provided in the guidance are summarised below:

1. Specialist supporting another adviser’s interaction – where the ‘principal’ adviser (who would be subject to the registration requirement) engages an external specialist to provide technical expertise and attend discussions with HMRC, the specialist will generally not be required to register on the basis they are not dealing with HMRC in their own capacity;
2. Relationship with overseas expertise – where an overseas firm engages a UK firm to provide advice on a client’s UK tax affairs and the UK firm deals with HMRC in relation to those matters, the UK firm would be required to register as they are responsible for the interaction with HMRC;
3. Subcontractor supporting a principal adviser – where a tax adviser engages a subcontractor and the subcontractor undertakes all interactions with HMRC under the direction of the tax adviser (who remains responsible for dealing with HMRC on behalf of the client), the subcontractor is not required to register as they are merely supporting the tax adviser’s engagement rather than interacting with HMRC independently; and
4. Subcontractor acting independently – where a business provides consulting services to other tax adviser firms and does not independently interact with HMRC, it is not required to register in respect of these services. However, it would be required to register in respect of its interactions with HMRC on behalf of its own clients. This requirement would apply even if the consulting services made up the majority of the business’ services.

In broad terms, MTAR10150 sets out that where more than one business is involved in delivering services, it is necessary to consider who, in practice, is acting on behalf of the client in the interaction with HMRC. This includes considering whose authority the interaction is made under, how the interaction is presented to HMRC, and which person is responsible for managing that exchange. Contractual relationships and the way in which fees are paid will be indicative, but not determinative factors.

Sanctions and safeguards

MTAR30000 is an entirely new section of the manual to provide guidance on the FA 2026 sanctions framework and HMRC’s administration approach. In its overview, it states that the MTAR regime has been designed to be proportionate and enforceable, provide flexibility for genuine errors, and give tax advisers an opportunity to rectify the issue before action is taken.

Further detail on the various powers HMRC has available under the legislation can be found in our previous article on the MTAR regime, but broadly they include:

• Suspensions of registration;
• Financial penalties;
• Ineligibility orders; and
• Publication of details related to sanctioned tax advisers.

Sanctions may be applied to either tax advisers, ‘relevant individuals’, or both, depending on the circumstances.

The guidance sets out further procedural detail on each of the above sanctions (including relevant safeguards), building on the information available in FA 2026. It confirms, in relation to suspensions of registration for behaving in a manner which “falls below the standards that might reasonably be expected of a tax adviser in their interactions with HMRC” (for the purposes of s232(2) FA 2026), that the relevant standard is HMRC’s standard for agents.

The guidance also contains information on how a tax adviser or relevant individual can challenge HMRC’s decision by way of review or appeal, including which decisions are appealable, when HMRC will offer a statutory review, and how a review will be carried out.

Other miscellaneous updates

Various other minor clarifications and updates were made to the MTAR manual. These include, most notably the following:

• Insolvency practitioners – MTAR10300 clarifies that an insolvency practitioner legally required to interact with HMRC on behalf of insolvent individuals and businesses is not required to register as they are acting in their legal role as office-holder under the Insolvency Act 1986 rather than as a tax adviser. The definition of an insolvency practitioner also applies to insolvency practitioners in territories outside the UK who exercise equivalent functions as set out in s228(10) FA 2026;
• Roles of relevant individuals – a further example has been added to roles that are likely to meet the definition of relevant individuals (under MTAR20400): any individual who makes strategic decisions about which tax advice services the business offers and how those services are managed or delivered;
• Obligations of relevant individuals – MTAR20500 has had an additional paragraph added to clarify that relevant individuals are not personally responsible for ensuring that a client’s tax affairs or payments are up to date; and
• Checks against registration conditions – MTAR20600 has had a paragraph updated to emphasise that registration conditions (both in relation to the business and its relevant individuals) must be met on an ongoing basis.

A reminder on registration timelines

The 18 August 2026 updates to the MTAR guidance coincided with the second phase of online registration going live. This requires advisers with Self Assessment or Corporation Tax accounts (but without an agent services account (ASA)) to register by 18 November 2026. The first phase of registration (18 May 2026 to 17 August 2026) targeted unregistered advisers without an ASA.

Potentially affected organisations and individuals should check whether they need to register by reference to the updated guidance and the provisions of FA 2026. However, the guidance also continues to make clear that registration is not a one-off event and registered advisers could still fall foul of the MTAR rules if they fail to maintain adequate control mechanisms, particularly in regard to meeting the registration conditions.

Two further registration phases are set to follow the second phase (for professional payroll service providers and financial services organisations) and therefore tax advisers within scope of the registration requirement should follow the relevant deadlines, and any further HMRC guidance released, closely. This is particularly important for financial services organisations, as their relevant deadline for registration has already been postponed once previously, in light of concerns regarding the applicability of MTAR to this sector.

For further information please contact:

• David Wren
• Catherine Anderson