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Self-Assessment Tax Return

Guidance for UK tax residents and non-UK residents on how to be tax-smart and pay tax bills

How to Pay Taxes in the United Kingdom?

UK tax laws are far from being mild. British citizens must pay taxes on all their income independent of its origin. Even non-UK tax residents must submit self-assessment tax returns if they get income in the United Kingdom.

At a certain point, all people staying in the UK have to file a tax return, for example, when they start receiving interest on their deposits or rental income. Imperial & Legal’s immigration advisors can help you optimise your tax burden. This article will provide short guidance for UK and non-UK residents and how they can use the rules of the British tax system in their favour.

What Is Self-Assessment Tax Return?

The UK taxation body HM Revenue and Customs (HMRC) has a special self-assessment system that they use to collect income tax from individuals, including self-employed and company directors. If you are an employee on payroll, with no other income worldwide (other than in the UK), you don’t need to send a return unless you’ve been told by the HMRC to do it. Seniors and people living off personal savings do not have to report to HMRC either.

If you are considered a UK tax resident in any reporting year, you need to fill in and send your tax return by the given deadline. In a tax return, you must report any income you have earned that is not covered by payroll, or PAYE (Pay As You Earn).

Experienced Imperial & Legal advisors can assist you with any taxation issue and help you correctly fill in and submit your tax return as well as choose the best possible way to optimise your taxes.

Who Must Submit Self-Assessment Tax Return?

You are required to fill in and submit a self-assessment tax return in a tax year (6 April – 5 April) if you meet any of the following criteria:

  • You were a UK company director
  • You were a self-employed sole trader with income over £1,000
  • You were a partner in a UK-registered partnership
  • Your overall taxable income was over £100,000.

Any additional income over £2,500 is tax-free. Here is the list of taxable sources of income:

  1. Rental income (even if you are a non-UK tax resident)
  2. Capital gain from selling an expensive property, for example, real estate
  3. Interests, return on investment and dividends
  4. Commissions and tips
  5. Grants and support payments (for example, COVID-19 pay-outs)
  6. Foreign income (only for UK tax residents).

When Else do I File Self-Assessment Tax Return? 

  • To prove that you are self-employed and are eligible to apply for tax-free childcare or maternity allowance;
  • To claim some income tax reliefs.

What Are the Deadlines for Submitting Tax Returns?

A tax year in the UK starts on 6 April and ends on 5 April of the following year. You have up to nine months (depending on the submission method) to prepare and send your tax return. The same deadline applies to paying your tax bills and your first payment on account if required.


Deadlines for the 2021/2022 tax year



Register for self-assessment

5 October 2022

Paper tax return

Midnight 31 October 2022

Online tax return

Midnight 31 January 2023

Payment of income tax

Midnight 31 January 2023

If your income tax is over £1,000, you must make the first payment on account that equals your current tax liability. It is done in two instalments: 50% while paying your current tax bill (till 31 January) and 50% till 31 July of the following tax year.

If you have missed the deadline, you must send a tax return anyway, but you will have to pay late-filing and late-payment penalties. The minimum penalty is £100 for less than three months of delay. If you delayed your payment for more than three months, HMRC will calculate the penalties based on how late you are.

Submitting Tax Return

If you are on payroll and do not have any additional sources of income, your employer will pay income tax for you. Note that job offers usually show annual gross salaries. For individuals, income tax is progressive and ranges from 0% to 45%.

All other categories of taxpayers, especially UK residents, must file self-assessment tax returns themselves. If you do not know what your residency status is, you can find out by doing a Statutory Residence Test.

There are three ways to fill in and submit your tax return:

  • Online on the government website
  • Through an accounting software 
  • Send a paper one by post.

Before filing a tax return, you must obtain a 10-digit UTR number and register with HMRC. You can fall into one of the three categories of taxpayers:

  1. Self-employed
  2. Partner or partnership
  3. Other categories.

Tax Return for Non-UK Tax Residents

Even if you are not a resident for UK tax purposes, you will have to pay taxes on the income you have earned in the UK, e.g. rental income or capital gains tax.

In this case, Imperial & Legal advisors will help you submit your tax return on time and pay all your tax bills from the conform of your home.

Tax Optimisation in the UK

The British tax system offers legal tools for tax optimisation from tax-free allowance to tax benefits for non-domiciles.

Some tax reliefs are granted automatically, others must be claimed in your tax return.

Remittance Basis

UK tax residents who are not UK domiciles (mainly born outside the country) can use a special taxation regime that is called remittance.

A remittance basis means that taxpayers can only declare and pay taxes on income received in the UK or remitted here.

Every tax year, a taxpayer decides whether to use a remittance basis or not since it also has certain restrictions. For example, you will not be able to benefit from a tax-free income allowance. This regime is usually used by foreigners who earn significant income outside the UK. You can claim remittance only by filing your tax return.

If a foreign national has been a UK tax resident for seven out of nine years before the current reporting period, they will have to pay £30,000 for using remittance. For 12 out of 14 years of UK tax residence, you will have to pay up to £60,000 in remittance fees. Finally, if you have spent 15 out of 20 tax years in the UK as a tax resident, you will not be able to use a remittance basis.

Experienced Imperial & Legal advisors will help you decide whether you should apply for remittance or draft a roadmap for you to optimise taxes for the preceding, current and following tax years. The right decision often requires accurate calculations. If the remittance option is chosen, Imperial & legal will be able to assist with filing a tax return.

Mistakes While Preparing a Tax Return

It is not so easy to fill in a tax return; it requires expertise and time. It is not rare that taxpayers are fined for making mistakes in their returns or missing deadlines. 

The key things you should be aware of are expenses you can claim, what sections to fill out and which ones not and what information to provide. Another thing is paying your tax bill. If you cannot pay all of it in one go, you should contact HMRC to get a budget payment plan so that you can pay in instalments. However, you might not be allowed to use it if you have not paid your previous tax bill (sometimes, HMRC allows to include the debt in the budget payment plan).

We strongly recommend our clients file their self-assessment tax returns with the help of our tax specialists. It will save you time and protect you from missing a deadline or paying too much tax. We will support you in the following:

  • Provide consultations and reply to your queries
  • Calculate the tax you need to pay in different scenarios and help you select the best solution for your circumstances
  • Register you with the HM Revenue and Customs (HMRC)
  • Fill in and submit your return to HMRC.

Our specialists can help you solve any challenges associated with Self-Assessment, from self-employment to foreign income. We will register you for self-assessment if you have not been before. We will make sure all the sections and supplementary pages relevant to you are filled out correctly. Our target is to protect your money while making sure you comply with all tax laws. 

Successful stories of our clients

UK tax return for a spouse visa holder
English tax return for a client with an Innovator visa

FAQ about self-assessment tax returns

How to register for self-assessment for self-employed?

The deadline for registration is 05 October of the next tax year. If we take the 2021/2022 tax year as an example, you will start getting penalties after 5 October 2022 if you do not register before that.

If you are a self-employed submitting your first tax return, follow these steps:

  1. Log in to your HMRC account on the government website and register for self-assessment. To access your account, you need a login and password. If you don’t have an account yet, you need to create one.
  2. Ten days after you apply for registration with HMRC, you get a UTR number. If you applied outside the UK, you will have to wait for 21 days. You will need UTR to submit your tax return. 
  3. Look out for an email with an activation code for your tax return submission. Enter the code to complete and submit a tax return online.

How can I register for self-assessment if I am on payroll?

The registration process is very similar to the one for self-employed. However, you will not be able to register online. You will have to download and fill in an SA1 form and post it to HMRC. You should receive your UTR number by post ten days later if you have applied inside the UK and 21 days if you have applied outside the UK.

Once you have your UTR, follow the same steps above. Sign in on the government website, register for self-assessment using your UTR, get an activation code and file a tax return.

If you have doubts while completing your tax return, feel free to contact Imperial & Legal for help.

Can I amend my tax return if I have already submitted it to HMRC?

Yes, you can. You may need to update your self-assessment tax return for various reasons. For example, if you have made mistakes.

To make changes to your tax return, you need to complete and submit a new tax return with updated information. You can either do it online or by post, explaining the reasons for updates in the attachment. Let’s look at it step by step:

  1. You download and print out official tax return forms.
  2. You fill in the forms and note down “amendment” on the pages which you have updated. Note that you must include your full name and UTR in your self-assessment tax return.
  3. You send the updated version to HMRC.

Based on your updated self-assessment tax return, your tax burden will be reassessed. You will have to either pay additional taxes or claim a rebate.

You can update tax returns for the last two tax years without notifying HMRC. However, if you need to make changes to older tax returns, you must notify HMRC first. You must provide details of:

  • what tax return you need to update
  • why you paid too much or too little tax
  • how much you need to pay or get refunded.

How long does it take to get a refund if HMRC confirms that you overpaid your tax?

It usually takes up to four weeks to get your money back. It will be transferred to the bank account you specified while filing a self-assessment tax return.

If you have an upcoming tax payment due in 35 days, HMRC can choose to reduce what you owe them instead of refunding you the money.

Under what circumstances can I appeal against a late-submission/late-payment penalty?

The government website lists the accepted reasons that can prevent law-abiding taxpayers from not declaring their income and paying tax bills on time. Here are some of them:

  • your partner or another close relative passed away shortly before the tax return or payment was due
  • you were in the hospital which prevented you from dealing with your tax affairs
  • you had a serious or life-threatening illness, including COVID-19
  • your computer or software failed just before or while you were preparing your online return
  • technical issues with HMRC online services
  • a fire, flood or theft prevented you from completing your tax return
  • postal delays that you could not have predicted.

The above excuses are considered reasonable only if you are a conscientious taxpayer and send your return and pay your tax as soon as possible after the situation is resolved.

Need to file a self-assessment tax return?

Our tax experts have years of experience in helping clients to file their self-assessment tax returns. Contact us to get individual tax consultation.