Self assessment and personal tax: questions answered

Self Assessment catches directors, landlords, subcontractors and anyone with untaxed income. This hub covers who has to file, what goes on the return and how to fix things when a deadline has already passed.

How do I complete a Self Assessment tax return as a dentist, contractor or consultant? The return itself is the same form, but the entries differ. Dentist associates report self-employed income after scheme deductions, contractors must consider IR35 status on each engagement, and consultants often mix self-employed and dividend income across several clients.

How does a CIS tax refund work and what affects how long it takes? Contractors deduct 20% (or 30% if you are not verified) from your gross pay under CIS, before your actual costs and personal allowance are taken into account. A Self Assessment return sets the deductions suffered against your real tax bill, and any excess is refunded.

How do I catch up on two years of late CIS subcontractor tax returns? You file each overdue year as its own separate return, using that year's CIS statements, income and expenses. Two years missed usually means two sets of late filing penalties and interest, but CIS subcontractors often find the underlying tax position is a refund rather than a bill.

How do I report rental income on a UK tax return? Rental profit goes on the property pages of your Self Assessment return: total rent received, less allowable expenses such as letting agent fees, insurance, repairs and service charges. Mortgage and other finance costs are not deducted from profit; instead you get a 20% basic rate tax credit against your bill.

How do dual UK and overseas tax returns work, for example with Italy or Spain? If you are UK tax resident with income or gains arising in another country, such as rental property in Italy or Spain, that income is normally reportable in the UK on the foreign pages, alongside any return required locally. Double tax treaty relief or a foreign tax credit stops the same income being taxed twice.

How do I appeal an HMRC late filing penalty? You can appeal a Self Assessment late filing penalty within 30 days of the penalty notice, either online through your personal tax account or by post using form SA370, by showing a reasonable excuse that applied throughout the delay and that you filed as soon as it was resolved.

Do I need to file a Self Assessment return this year? You need to file if you were self-employed with income over £1,000, a company director receiving dividends or untaxed income, a landlord, had income over £150,000, need to pay the High Income Child Benefit Charge, or have capital gains or foreign income to report.

Rates, thresholds and deadlines quoted here reflect the 2026/27 UK position and current Companies House and HMRC guidance. Check GOV.UK, or ask us, before relying on them for your own company.