15 Jun 2026
By James Findlay, Senior Tax Manager, KPMG UK
For many businesses, dealing with HMRC has long been seen as a routine part of operating in the UK tax system.
But with its new tax adviser registration regime now coming into force, the rules around who can interact with HMRC on behalf of clients have changed significantly and the implications are wider than many organisations may realise.
Introduced under the Finance Act 2026, the rules are designed to raise standards across the tax advisory market and tackle harmful tax advice. However, the changes extend beyond traditional accountancy and tax advisory firms with in-house teams, payroll providers and overseas advisers who engage with HMRC on behalf of others now falling within scope.
This is not simply another compliance exercise; rather businesses should see these changes as a significant operational and governance issue that needs immediate attention.
A major expansion in HMRC oversight
Tax practitioners who interact with HMRC on behalf of clients must now register formally with HMRC and meet a series of ongoing conditions. It is also now an offence for a tax adviser to engage with HMRC in relation to a client’s tax affairs unless they are registered or fall within a specific exemption.
The consequences of getting this wrong could be serious as HMRC has powers to refuse to engage with unregistered advisers, impose penalties and suspend registrations where conditions are not met. In practice, that could prevent businesses from carrying out core client services.
Importantly, the regime does not just apply at organisational level. “Relevant individuals” who play a significant role in managing or overseeing tax adviser activities or who make decisions about how those activities are run, must also register personally.
Both the firm and its relevant individuals must continue to meet the registration conditions on an ongoing basis. If standards slip, HMRC can suspend registration, including where behaviour falls below what might reasonably be expected of a tax professional.
While ministers have stressed the regime is aimed at tackling genuinely harmful tax advisers and that HMRC will apply the powers proportionately, businesses should not underestimate the seriousness of the changes. For those whose operating model depends on engaging with HMRC, failure to comply could become a major operational risk.
What businesses should be doing now
Businesses should start by identifying where interaction with HMRC takes place across the organisation and who is responsible for it. The focus should extend beyond the tax team, with finance, payroll, HR and operational teams all potentially falling within scope depending on how the business engages with it.
Any activities involving contact with HMRC on behalf of another party should be reviewed carefully, as these could trigger a registration requirement. While exemptions exist, these are expected to be narrowly defined and should not be assumed without proper review.
It is also important to identify any “relevant individuals” under the legislation like those responsible for managing or overseeing tax adviser activities and ensuring appropriate screening and governance processes are in place. Registration should not be treated as a one-off exercise as HMRC will be able to request evidence of ongoing compliance with the registration conditions.
Businesses should also consider whether additional training or clearer internal guidance is needed to comply with HMRC’s expected behavioural standards. Some may decide to limit HMRC interaction to avoid registration requirements but that will require robust controls and monitoring.
HMRC is phasing registration by cohort, with each one having a three-month application window. Interaction can continue during that, but if the window is missed, interaction with HMRC must stop until an application has been made and accepted.
That’s why businesses within scope should now be identifying the relevant timelines and keeping track of further HMRC guidance as it emerges.
