How to authorise a UK tax adviser: form 64-8
What HMRC authorisation does, what it does not do and how to keep control of your tax affairs.
Short answer: Form 64-8 or HMRC's online authorisation process lets a tax adviser deal with HMRC for the matters you approve. It does not transfer your legal responsibility for the return or make an adviser responsible for facts you have not checked. Read the scope, keep copies and remove authorisation when the engagement ends.
Key points
- Authorise only the adviser and taxes you need help with.
- You remain responsible for accurate information in your return.
- Keep a copy of the authority and the date it was granted.
- Tell HMRC when an adviser should no longer act.
What authorisation allows
An authorised agent can usually discuss the relevant tax affairs with HMRC, receive information and deal with correspondence within the authority's scope. The precise process depends on the tax and whether the authorisation is online or paper.
What it does not allow
Authorisation is not a blank cheque to make decisions without your knowledge. Confirm what will be filed, what evidence supports it and when you will be asked to approve the final position.
For non-residents
A residence claim, UK rental income or property disposal may involve several HMRC services. Make sure the adviser can see the relevant record and that the authority matches the work you have agreed.
Written and reviewed by Matthew S Manderson CTA ATT AMIT
Reviewed 3 September 2026. General guidance only; tax treatment depends on individual facts.