This information applies to England, Wales, Scotland and Northern Ireland

If you are working for an employer who is taking PAYE (pay as you earn) tax and national insurance from your regular wages, and you do not have any other income, you do not usually need to complete a tax return form.

You will need to fill in a Self Assessment tax return form if you are self-employed, a company director, a partner in a business or if you have income that is not taxed at source, for example, rental income.

A complete list of people who need to fill in a tax return can be found on the Directgov website at www.direct.gov.uk or in Northern Ireland on the Nidirect website at www.nidirect.gov.uk.

If HM Revenue and Customs (HMRC) thinks you may have income which needs to be taxed under Self Assessment, it will send you a tax return to complete. However, it is your responsibility to tell HMRC if you think you have income which needs to be taxed.

You can complete a tax return online or on paper. If you have not received a paper tax return or a notice to complete an online return and you think you need to complete one, contact your tax office or the HMRC Self Assessment helpline on 0845 900 0444.

If you fill in your tax return on paper, you must send it back to HMRC by no later than 31 October following the end of the tax year.

If you complete your tax return online, you must do this by no later than 31 January following the end of the tax year.

If you don't stick to these deadlines, you will be charged a penalty.

For more information about Self Assessment, see Self assessment.

For more information about tax returns, see Tax Returns.

For more information about PAYE, see The Pay As You Earn (PAYE) system.

Other Frequently asked questions about tax:

• Do I still have to pay tax now that I am over 65?