Self-assessment document checklist

With increased digitalisation it is unlikely that a paper Self-Assessment Tax Return will have been issued to you, although HMRC may still have sent a Notice to Complete. Either way, please read on, so that your tax affairs can confidently be left with us.

To do that we need the documentation set out below. Where we prepared last year’s Return, you will also have a Data Sheet containing the figures we used. Please look through it, make any relevant alterations, and send it back with the supporting paperwork.

Making Tax Digital

For non-VAT-registered sole traders, businesses and landlords above the income threshold, Making Tax Digital for Income Tax came into effect on 6 April 2026, and more digitalisation from HMRC is in progress. In the meantime, Self-Assessment Tax Returns still have to be completed and filed — and some pensioners will still need to complete one for the year above.

Changes to tell us about

If any of the following apply to you, please let us have the full details.

• Tax and Welfare Credits. Although these are not part of the Tax Return, the information needed to claim them comes from your completed Return.
• Personal (including Stakeholder) pension relief. You can only claim this on your Return if you pay for the policy yourself, and a certificate is essential. You may have to press the pension or assurance company for the correct piece of paper — only a certificate is of value in preparing your Return, not marketing material, statements or valuations.
• Filing online. All Returns have been filed online since 2007. HMRC requires paper copies to be filed by 31 October 2026; online Returns can be filed by 31 January 2027. For most of our clients this is academic, as most Returns are filed before 31 July — which gives certainty about the true liability due on that date. Any Return filed after the due date carries a penalty that will not be reduced, and daily penalties have applied since 30 April 2012.

Timetable

It greatly assists us to give you the best service if you gather all the relevant data now, and once you are certain you have all of it, send it together with any official HMRC paperwork. We will compile the data and send the Return to you for your formal signature of approval.

Most of this is gathering documentation from third parties, which should be in your possession by the end of April each year — though some of it you may be able to download yourself. Please fold the papers to avoid the “Large Letter” postage rate; we would prefer to deal with other matters by email.

Any tax return data received after 1 October 2026 will, sadly, have to be charged at a higher rate, as accountants’ offices tend to be highly stressed by latecomers.

Note: no responsibility

No responsibility can be accepted for any omissions or errors arising on these tax returns. Mistakes have proved to be expensive, and HMRC charges penalties and interest if a Return is not submitted within the strict time limits. Our practice has a proud record of filing most clients’ Returns by 30 June annually — that way clients avoid an artificial payment on 31 July.

Document checklist

Year ended 5 April 2026. Since 2016, many third parties let those registered for online services download some of these documents.

For everyone — certificates for any of the following

• Pension contributions made to a financial institution
• Gift Aid payments
• Interest on qualifying loans
• Capital Gains transactions — stocks, shares, properties, chattels and businesses — with documentation
• If you or your partner claimed any Tax (Welfare) Credits: the claiming partner’s surname, National Insurance number, and income level to determine the highest rate of tax paid
• Child Benefit — if you or your partner received it, please tell us the amount, the number of children involved, who claimed, and which of you is the higher earner

For the employed

• Form P60, showing earnings for the year — obtainable from your employer
• Form P11D, showing company benefits over the year — obtainable from your employer
• Payslips, and evidence of any foreign earnings with foreign tax deducted
• Details of share options awarded or exercised, or participation in any other share plans such as profit-sharing schemes

For the self-employed

See also our separate request for books letter.

• Your financial accounts for the year that ended within the fiscal year (6 April 2025 to 5 April 2026). Not every self-employed client has accounts made up to 5 April annually — but with the Change of Basis Period introduced on 6 April 2024, we recommend adopting 31 March or 5 April. Check with us if you are in doubt.
• Normally your accounting records would be the free ABC Accounts Book or another suitably approved substitute, such as FreeAgent or accounting software. These used to be made up from cash books, petty cash books, purchase and sale ledgers, invoices, expenses and receipts, but compulsory digital record keeping has been phased in since 6 April 2020.

Rules introduced on 6 April 2017 reclassify self-employment when supplying services to any public body authority — this includes the service industry — and were tightened from 6 April 2021.

For investors — including Bitcoin and other cryptocurrencies

• Dividend vouchers, from publicly quoted companies as well as owner-controlled companies
• Interest certificates from your bank or building society — or account statements, or an up-to-date passbook. Where accounts have been closed or opened, specific dates are required. With internet banking you can often access and print these early.
• Tax deduction certificates issued by your bank, if you have not downloaded them
• Rent records, if you own a property or let one out — see the rental checklist below

Pensions and social security

• Certificates covering income from trusts or estates
• Pension book or pension statement

Student loan repayments

• Statement — the date the loan applies is essential, as there are two separate tax treatments

Rental accounts — document checklist

Ask us for a separate worksheet.

• Address of the property
• Whether the property is let furnished or unfurnished. Since 6 April 2017 no wear and tear allowance is allowed.
• Income: details of rent received
• Expenditure: ground rent; management fees; council tax and water rates; repairs (full details and bills); insurance (building and contents); loan interest certificates; legal and accountancy bills

On loan and mortgage interest: from 6 April 2017 the amount that could be deducted was reduced by 25% each year until 100% was reached on 5 April 2020. This could place you in a higher tax rate.

Extra copies

Extra copies of these checklists can be downloaded free of charge from this website — please check back from time to time for updates. We also post daily tax briefings on our Facebook page, M Levin & Co, which you are welcome to follow. Your email address would be appreciated so we can update our records. Thank you.