64-8 – Authorising your Agent

This 64-8 form is used to authorise a Tax Agent to be able to liaise with HMRC on your behalf. The official location for this form is below:


Your tax agent often needs to liaise with HMRC on your behalf via telephone or post. To enable this you need to authorise your agent or me as your tax agent.

As your authorised tax agent I will receive copies of most HMRC correspondence sent to you. This helps me respond to HMRC correspondence quickly and accurately. This is particularly useful if you travel a lot or are in between homes so that I can act proactively to HMRC correspondence.

HMRC accept only 2 methods of authorisation.

Online authorisation
If you have a 10 digit SA reference number eg.3456798765 then I can request authorisation myself online and you will be sent a letter in the post with a short code usually within one week.Pass me that code and that completes my authorisation.

Paper based authorisation (Form 64-8)
If you do not have a 10 digit SA reference number or are not set up under the new Self Assessment system then you need to complete the following form.

This 64-8 form will only be accepted by HMRC if it is signed by you and posted direct to the Longbenton address shown on page 2 of the form.

This form takes a long time to be processed by HMRC often more than 2 months so the earlier it is sent to them the better.

You can cancel my authorisation at anytime with a telephone call to your tax office or by submitting a new authorisation to supersede the current one. Cancelling the 64-8 HMRC agent authority is normally effective immediately but sometimes you only want to change the authority or if you have more than one advisor this is best notified to HMRC by letter.