For many people, filing their taxes is scary. HM Revenue & Customs (HMRC) are specific with what they expect from you, and depending on your circumstances, you could be expected to provide more information than someone in a similar situation.

Understanding your own financial circumstances is essential, and this alone can be tricky to navigate. Add in the fact that filing your taxes wrong can result in penalties and fines, and people are often intimidated by the whole experience.

Luckily, there’s a slight workaround – form 64 8. It allows taxpayers to avoid dealing with the mess of filing taxes, regardless of whether you’re employed, self-employed, or the director of a limited company.

But there’s still some confusion as to what form 64 8 is and how it can be used to file your taxes. That’s why we’ve created this article to clarify that for you and answer all questions related to form 64 8. Let’s dive in.

Form 64 8 allows you to authorise a tax agent – such as an accountant or advisor – to act on your behalf and arrange your tax affairs directly with HMRC. This involves filing your tax returns, viewing your tax history, and changing your details.

GDPR and data protection laws have meant that HMRC is unable to discuss your tax affairs with anyone besides yourself without your permission. Therefore, form 64 8 was created in order to help those who want to outsource their tax filings to a professional or someone else on their behalf. Suppose you want to authorise an agent who is not working in one of the mentioned fields, i.e. a friend or family member. In that case, they can be nominated as a ‘trusted helper’.

The main benefit of filing a form 64 8 is that a professional deals with your tax affairs, mitigating mistakes that can often lead to hefty penalties and fines.

Whether you are authorising an agent for your Self Assessments, Corporation Tax, or Tax Credits, HMRC has a strict policy on how they expect you to file your tax information and details. This is because the information you provide determines how much tax you are liable to pay and, if wrong, can significantly impact your tax records.

It may result in you paying more taxes than necessary or the opposite, where you end up paying more. This results in extra time and work for both you and HMRC as mistakes are addressed and fixed.

There are also instances where individuals and corporations submit incorrect information in order to avoid paying too much tax.

In order to combat all of this, HMRC has set strict guidelines and introduced large fines and penalties for those who provide misinformation, regardless of whether it has been done intentionally or not.

Although penalties are often reserved for those who have deliberately provided the wrong information, those who have done so carelessly can often expect to be on the receiving end of a fine. This is why filing information correctly the first time is crucial.

If your tax affairs are fairly straightforward, you may find that it’s far more convenient to file them yourself. However, if your tax affairs are complicated – or if you are unsure of how to file your information correctly – it may make more sense to allow your accountant or tax advisor to do this on your behalf.

Not only do they have expert knowledge of how tax filings are done, but they also have access to your tax records. They can help you file the exact information that HMRC wants to see.

The actions an agent can take on your behalf depend on your tax situation. For instance, if you are paying taxes under the Pay As You Earn (PAYE) system, they will have authorisation for different tasks and access to different information compared to if you pay taxes by filing a Self Assessment. Let’s look into this in more detail.


Your agent will have the ability to:

  • View your employment history – e.g. who you are currently working for and who you have worked for in the past.
  • View your taxable benefits – e.g. if you receive private health insurance, dental insurance, a company car, accommodation, gym memberships, etc.
  • View your pension history – e.g. which pension scheme you are registered with and how much you are contributing each paycheck.

Self Assessment

Your agent will have the ability to:

  • File your tax return.
  • Submit your tax-related details – e.g. how much you earn, your sources of income, overall expenses etc.
  • View how much tax you have paid and how much is still owed.
  • Change your registered contact and bank details.
  • View your previous tax returns and discuss them with HMRC.
  • Cancel your Self Assessment registration.

Corporation Tax

Your agent will have the ability to:

  • View company information – e.g. the number of employees, existing clients, etc.
  • View the company’s financial information – e.g. revenue, expenses, profit, etc.
  • Change your registered contact details.


Your agent will have the ability to:

  • Change and submit your VAT details.
  • Sign documents on your behalf.
  • View your VAT history and discuss them with HMRC – e.g. previously submitted returns, calculations, amounts owed and paid, etc.
  • Appeal penalties or fines.
  • Cancel your VAT registration.

Tax Credit

Your agent will have the ability to:

  • View personal and financial information related to your Tax Credit claim.
  • Act on your behalf.

Construction Industry Scheme (CIS)

Your agent will have the ability to:

  • View your returns.
  • View your subcontractors’ income.
  • View your subcontractors’ deductions.

Agent authorisation does not allow them to:

  • View and oversee your Making Tax Digital services on your behalf.
  • Create new accounts – e.g. Self Assessment account – with HMRC on your behalf.

Yes, authorising your agent to act on your behalf does not mean that they become responsible for your tax affairs – that responsibility still lies with you. This means that should documents and information be filed late or wrong, you will have to bear the consequences.

Therefore, it’s important to ensure that your agent of choice is competent for the role and that you trust them to act on your behalf. This is especially relevant if you have designated a trusted helper, such as a friend or family member.

Submitting a form 64 8 is incredibly easy. You can either fill it out online or print it and send it via post.

You will need to fill in the following information:

  • Your name, address, and contact details.
  • The agent’s name, address, and contact details.
  • The services you would like the agent to act on your behalf of – e.g. Self Assessment.
  • Your National Insurance Number and/or Unique Taxpayer Reference (UTR).
  • Agent Government Gateway identifier – only applicable for Construction Industry Scheme)

Yes, you can have multiple agents who deal with your tax affairs on your behalf. To set this up, you simply need to file a new form for each individual agent who is representing you. Keep in mind that each agent's exact roles and services must be outlined in the form so that HMRC knows who to ask for certain information.

In most cases, it takes up to 24 hours for HMRC to process 64 8 forms and update your agent list. However, if you fill in a 64 8 form for a limited company, it can take up to 72 hours to process.

Authorising an agent for Child Benefit is possible, but not using the 64 8 forms. Instead, you must use form TC689.

Regarding filing your taxes, form 64 8 can be used to authorise an agent to deal directly with HMRC. The agent is typically an accountant or tax advisor that has expert knowledge on the topic. The form is usually submitted by taxpayers who have complicated tax affairs. But, it is also used by those who simply do not have the time to go through the process.

Form 64 8 can be submitted by those in employment, self-employment, or as a limited company.