Caroline Miskin, ICAEW tax manager explains: ‘Anyone who is self-employed, has income from letting property, receives high levels of investment income, or has capital gains tax to pay must complete a self assessment return.

‘You may also need to file a return if your annual earnings exceed £100,000. However, this list is by no means exhaustive; if you aren’t sure whether you need to complete one, contact HMRC directly.’

Here are some useful tips about completing your self assessment on time:

Work out your income from self-employment and property: Keeping good records as you go along makes it easier to work out income from self-employment and from letting property. You will need a summary from your records to complete your tax return

Get everything together: Before you start filling in your return, gather your important documents together. You will need details about your employment and pension income, find your P60 and if your employer gives you other benefits, your P11D which outlines details of reimbursed expenses and benefits. You will also need your P45 if you have changed jobs during the year

Don’t forget investment income: You will also need any dividend vouchers, interest summaries from banks and building societies and details of any other investment income that is held other than in an Individual Savings Account

Gather details of assets you've sold: You’ll also need to gather details of any assets you’ve sold in the year that may be liable for capital gains tax

Pension contributions and Gift Aid: Make sure you keep details of any pension contributions made. You will also need details of all your gift aid payments – have you sponsored a friend to run for charity?

Keep proof: Make a copy of your completed tax return and keep it, and proof of posting, on file. Keep all paperwork for 22 months from the end of the tax year to which they relate if you are employed or a pensioner. If you are self-employed or letting a property, you should keep all paperwork for five years and 10 months

Caroline Miskin, ICAEW tax manager adds: ‘If you are not sure whether HMRC is expecting you to file a tax return you should contact them as soon as possible.

‘A Notice to File a Tax Return must never be ignored but HMRC will agree to cancel the notice and withdraw the requirement to file a return if there isn’t a need to complete one.’

The deadline for telling HMRC about a source of income which started in the 2016/17 tax year was 5 October 2017 but if this deadline has been missed it is still possible to avoid penalties by registering with HMRC and filing and paying the tax by 31 January 2018.