UK tax agent registration and client authorisation
HMRC has published guidance for tax professionals registering as tax agents and obtaining authorisation to represent clients. The resource covers the registration process and requirements for acting on behalf of clients in the UK tax system. This applies to customs brokers, freight forwarders, and export service providers who handle tax compliance for their merchant clients.
Photo: Leeloo The First / Pexels# UK Tax Agent Registration and Client Authorisation
HMRC has updated its guidance on how tax agents register and obtain authorisation to act on behalf of clients. Published on 28 April 2026, the guidance provides support and resources for professionals seeking to formalise their representation role in the UK tax system.
Who needs to register
Tax agents—including customs brokers, freight forwarders, and export service providers—must register with HMRC if they wish to act on behalf of clients in tax matters. This is particularly relevant for shippers and logistics providers who handle customs declarations, tariff classification, landed-cost calculations, and other tax-adjacent compliance on behalf of merchants.
Registration and authorisation process
The guidance covers the steps required to register as a tax agent and obtain client authorisation. Agents must ensure they have proper written authority from clients before representing them, and must comply with HMRC's standards for professional conduct.
For customs and international trade work, this means agents handling:
- Customs invoices and value declarations
- Tariff classification and HS code selection
- Duty and landed-cost estimates
- Import/export documentation
...should ensure their client relationships are properly documented and authorised under HMRC's framework.
What this means for shippers
If your business uses a customs broker, freight forwarder, or tax advisor to handle declarations, valuations, or tariff matters, confirm that your agent is properly registered and authorised with HMRC. This protects both parties and ensures compliance with UK tax administration requirements.
For detailed information on how proper agent authorisation affects your customs invoice preparation and landed-cost calculations, see our guide to calculating landed cost.
