Mandatory agent registration – publication of HMRC guidance

HMRC published the following guidance on agent registration on Tuesday 17 February:

• Check if and when you need to register as a tax adviser with HMRC
• Check if you meet HMRC’s conditions to register as a tax adviser

This is the first guidance published by HMRC on agent registration, largely aimed at tax advisers who are not currently registered and do not have an Agent Services Account.

The guidance published provides new information on the timeframes for registration, set out below:

• Registration will open from 18 May 2026.
• Existing agents who have a Self-Assessment or a Corporation Tax account (but not an Agent Services Account) will need to register from 18 August 2026.
• Agents that only provide third-party payroll services on behalf of clients and do not interact with HMRC in any other way, will need to register from 18 November 2026.
• Existing agents who already have an Agent Services Account will not need to register and HMRC will contact those agents via their Agent Services Account when they require further information from them. In the meantime, we recommend all agents ensure their contact details within their Agent Services Account are up to date.

Some additional new details from the initial guidance include:

• Agents will have three months from the date they are required to register to apply for an Agent Services Account.
• Agents can continue to interact with HMRC during these three months and whilst HMRC consider their registration.
• Agents can choose to register early from 18 May 2026.

We would also like to clarify the following points in respect of the examples provided in HMRC’s guidance on identifying relevant individuals:

• Businesses with 5 officers or less – A firm with five or fewer officers must identify all officers and any employees who also meet the definition of ‘relevant individual’ in the legislation.
• Businesses with 6 officers or more – A firm with six or more officers must follow a two-step process:
  • Firstly, they must identify all employees and officers who meet the definition of ‘relevant individual’ in the legislation. 
  • If there are fewer than five officers identified in step one, they must identify further officers (for example non-tax partners) to ensure there are a minimum of five officers identified, in addition to any employees who meet the ‘relevant individual’ definition.

The number of relevant individuals is not capped at five.  We do not believe this is clear from the guidance published by HMRC on 17 February and have spoken to HMRC about this, who have taken this away to consider updating the guidance. 

There remain significant gaps in this guidance, and we continue to urge HMRC to publish more detailed guidance. In the meantime, we are currently updating our Frequently Asked Questions on Agent Registration, which can be accessed from the Mandatory Registration with HMRC - FAQs | Chartered Institute of Taxation or Mandatory Registration with HMRC - Frequently Asked Questions | The Association of Taxation Technicians. 

We are in the process of organising a webinar for members, please keep an eye out for this on our website and in our member emails.