HMRC use your Self Assessment tax return to calculate the amount of tax you owe as a small business owner, freelancer or partnership. This article outlines which documents and records your accountant will need to prepare your Self Assessment tax return on your behalf.
Using an accountant for Self Assessment
Lots of people prefer to bring in the services of an accountant for their tax return, rather than tackling it themselves, but paying someone else to do it doesn’t mean your job is done.
Your accountant will need as much information as possible so they can complete and submit your Self Assessment tax return for you – especially if they’re to help you take advantage of any tax allowances and relief you might not be aware of.
We’ve put together a list of all the information you’ll need to provide to your accountant so they can complete your tax return. Remember, the sooner it’s in, the better!
Employment information
If you’ve been an employee or director, either through your own company or otherwise, you will need to provide information about the wages you received during that tax year, and any tax you’ve already paid on it.
You can normally do this by providing your accountant with a P60 or P45, which shows gross salary, tax deducted and any student loan deductions. You’ll also need to let them know about any Benefits in Kind you receive (such as a company car, for example), so give them a copy of the details you get from your employer.
Pensions
There are two sides to telling the accountant who is doing your Self Assessment about your pensions:
- Letting them know about income you receive from one (because counts towards your calculation for taxable income)
- Reporting any payments you make into a pension scheme so you claim tax relief on your contributions
If you receive an occupational pension you should provide your accountant with your P60 or the certificate of pension paid. You will also need to show your accountant how much pension you receive and your notification letter if you receive a state pension.
As a side note, you should also provide information on any other taxable benefits, such as amounts received and taxable lump sums.
Self-employment and partnership income
Your accountant needs to know about the income you receive as a self-employed person, whether you’re a sole trader, a partner in a partnership, or because you have your own limited company, and pay yourself dividends as well as a salary.
You’ll normally need to provide:
- Business records, including the bookkeeping
- Confirmation of your share of any partnership income
- Partnership interest income and the tax deducted
- Any other partnership income
Investment income
Any income you have made on investments must also be declared in the Self Assessment return, which is why you’ll need to tell your accountant about them. The table below shows examples of different types of investment income, and the document you’ll need to provide to your accountant.
| Investment Income Type | Documentation Required |
| Dividends from UK companies and/or unit trust including shares and/or units in place of dividends | Dividend/distribution vouchers which display the dividend amount and the date it was received |
| Expenses | List of all tax deductible expenses e.g. professional subscriptions, travelling expenses. If you’re not sure what counts as an allowable expense, don’t miss out! Double-check it with your accountant. |
| Gift Aid or Deed of Covenant payments | Gift Aid payment details including the name of the charity, date, amount given, and covenant details (confirmation showing you signed a Gift Aid declaration so the charity can claim tax relief on your donation) |
| Income from property | Any income you receive from property and records of relevant expenditure, including mortgage interest statements |
| Income from trusts, settlements, Deeds of Covenant and estates | R185 or certificates of income with tax deducted |
| Interest from banks and building societies | Certificates of interest and tax deducted |
| Other payments qualifying for tax relief | Lender’s statements displaying paid interest and tax relief given |
| Overseas income | Dividend vouchers and evidence of other income |
| Pension contributions you have paid | The details of any payments made into pension schemes including dates, amounts and policy details with copy documentation |
| Qualifying loans and mortgages | Lender’s statements displaying paid interest and tax relief given |
| Student Loan repayments | Details of payments made towards your Student Loan, with amounts and dates and copy statement displaying the balance as of 5 April |
Capital transactions
Your account will need information about any capital transactions taking place during the tax year covered by your Self Assessment tax return, such as:
- Disposal of a main residence if it was partly used for business
- Disposals made during the 2026/27 where gains exceed £3,000
- Capital losses
- Share securities bought, sold or take-overs
- Property acquisitions and disposals
- Other chargeable disposals, such as personal property you have disposed of worth over £3,000
Additional information
Your accountant may also need additional information from you when submitting your return. If you have any other income aside from the examples listed above, or tax deductions, gains or losses, you must provide your accountant with this information.
In need of a new accountant for Self Assessment season? We can help! Call 020 3355 4047 or get an instant online quote.
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