In this section:
Self Assessment for agents and advisers
Handling clients' personal tax affairs under Self Assessment - whether they are employed, self-employed or in a business partnership, is one of the areas of tax management you are most likely to be involved with as an agent or adviser.
This guide will show you what you need to do when you start to deal with your clients' personal tax affairs on their behalf. It shows you how to find the best software for your needs as well as some tips on how to manage multiple clients. It also directs you to detailed guidance to help your manage your client's personal tax affairs.
On this page:
- Managing Self Assessment Online for agents
- Choosing software for Self Assessment
- Forms we send to agents
- More guidance on managing Self Assessment
Managing Self Assessment Online for agents
You can use Self Assessment Online for agents service to file your clients' Self Assessment (SA) returns over the Internet. The service is secure and it's available 24 hours a day.
You can also use the service to:
- see your clients' statements online
- view their tax liabilities and the payments they've made
- make claims to reduce their payments on account
- change your client contact details online
- use the secure email service to send us queries and get replies
When you file a return online using the service you'll get an acknowledgement straight away. Using the service will also help your clients get any tax repayments that are due to them more quickly.
Register for online services for agents
To register for Self Assessment Online for agents you'll need a Self Assessment agent reference code. If you haven't got an agent reference code, you can get one by calling your local tax office.
Once you have your agent reference number, you can register for the Self Assessment for agents online service.
You can register and enrol for Self Assessment Online for agents through our online services registration page. You need to select 'register as an agent' and then choose Self Assessment (SA) for agents.
The registration process only takes a few minutes to complete. You'll have to:
- provide a few details about yourself
- choose a password - this must be between 8 and 12 characters, and contain at least one number (0 to 9) and one letter (a - z)
- make a note of your User ID - this will appear on screen and we'll confirm it by post within seven days
- create your agent identifier
Register as a new agent user through HM Revenue & Customs online services
Agent authorisation
Before you can deal with your client's SA tax affairs you'll need to be authorised. The easiest way to do this is to use the online agent authorisation service. You'll need to be specifically authorised for SA to deal with your client's SA affairs.
To authorise online you'll need:
- to have registered for the Self Assessment Online for agents service
- your client's unique taxpayer reference and post code - or you can use their National Insurance number
- the authorisation code we sent to your client - this begins with 'SA'
Using the online service means that you and your client don't have to submit a paper form 64-8.
More detailed guidance on agent authorisation
Get details of the online agent authorisation service
Self Assessment Online for agents
You can use Self Assessment Online for agents to file your client's SA tax returns online. The service is secure and you can use it day and night.
You can also see your clients' statements online, view their liabilities and payments and make claims to reduce their payments on account. You can use the service to change your client contact details too.
When you file a return you'll get an acknowledgement at once. Using the service will also help your clients to receive any tax repayments that they're due more quickly.
Managing users and assistants
When you're registered for Self Assessment Online for agents, you can set up other users - this allows different people in your organisation to use the service.
It can be a good idea to set up more than one person as a user so the service can be accessed if people are on holiday, off sick or away for other reasons. Setting up several users allows different people in your organisation to take responsibility for different processes or clients.
You can set up other people in your organisation as either 'users' or 'assistants'.
Users can:
- use registered and activated online services
- register for or remove services
- assign users and other assistants to services
- create and delete other users and assistants
- change their own registration details
Assistants have more limited access. You - and other users you set up - can set up one or more assistants.
Assistants can:
- use the online services assigned to them by a user
- send in returns and forms for you
- change their own registration details
Each user and assistant that you set up gets their own unique User ID.
Find out how to manage users and assistants
Setting up records
To use Self Assessment Online for agents you'll need to create client records for your clients. You'll need to give us specific details including your client's name and contact details, their unique taxpayer reference and your client reference.
You can locate your client by searching for:
- their surname
- their unique taxpayer reference
- your client reference
You can also view and download your client list.
See a demonstration of the Self Assessment for agents' online service
Forms we send to agents
Once you're authorised to act as an agent to deal with your client's Self Assessment tax affairs, we'll send you the following forms:
- SA310 - acknowledgement that we've received the return where this includes the calculation.
- SA300 - Statement of account. Your client can ask us to send this to you - but they won't get a copy as well.
- SA302 - tax calculation.
- SA323 - our estimate of your client's tax bill for the year.
- SA324 - surcharge notice.
- SA326 and SA328 - fixed penalty notices.
- SA327 - client account information sheet - we send this out in December and June each year. It shows all the transactions on all your clients' accounts for the last 12 months.
Choosing software for Self Assessment
When you file your client's tax return online using Self Assessment Online for agents you can use either:
- our software
- commercially produced third party software
Our software is free. You can use it to file the main Self Assessment tax return - form SA100 - and its supplementary pages.
Our software package also checks the return as you fill it in and does the tax calculations for you. You can also get free support from the Online Services Helpdesk on Tel 0845 60 55 999. Lines are open from 8.00 am to 8.00 pm seven days a week. You can also email us.
Email the Online Services Helpdesk.
You can also use commercial third party software to file your client's return online. Third party packages may also allow you to file the partnership return - form SA800 - and the trust return - form SA900 - as well as the main Self Assessment form.
Our website includes a list of third party software suppliers - we've tested their products to make sure their forms and supplementary pages can be sent over the Internet.
You may also be able to submit virus-free PDF attachments with the online return.
Find out about Self Assessment online software and see a list of third party software suppliers
More guidance on managing Self Assessment
You can find detailed guidance on managing Self Assessment for your clients' personal tax affairs in the Self Assessment section of this website.
The section covers:
- Self Assessment - the basics
- what you owe, how to pay, deadlines and penalties
- Self Assessment errors, refunds, investigations or appeals
- Self Assessment for self-employed people, partners and partnerships
- Self Assessment for personal representatives, trustees and non-residents
