If your earnings fall or stop part way through the tax year (from 6 April to 5 April the following year), you may have paid too much income tax on your earnings, savings or other income. If this is the case, you may be able to claim a tax rebate (when you’ve paid too much tax and get some back). You don't have to wait until the end of the tax year to do this.

To check whether you’re due a tax rebate, contact HM Revenue & Customs (HMRC).

If you have problems making a tax rebate claim and your income is low, you can request free help from TaxAid or, if you are aged 60 or older, Tax Help for Older People.

Most people in employment pay their income tax through Pay As You Earn (PAYE). This is a system for collecting income tax and National Insurance contributions if you:

• work for an employer
• get a pension from a previous employer or pension provider.

HMRC uses a tax code to tell your employer or pension provider how much tax to deduct from your wages or pension. This means the correct amount of tax should be deducted automatically from your pay or pension before you get it. However, mistakes are not uncommon and it’s up to you to make sure that you pay the correct amount of tax. For more information visit Citizens Advice.

If you decide to draw a large lump sum from your pension, often too much tax will be deducted under PAYE. If you have cashed in the whole fund, you can reclaim the overpayment straight away – contact HMRC. In other cases, your tax bill will be corrected either when you take a further payment from your pension, or at the end of the tax year, whichever comes first.

Once every three years or so, you may be sent a tax review form P810, so that HMRC can check it has all the right details. You can also request this from HMRC if you’d like them to check your tax code is correct. You should send this back as soon as you can or give details asked for by phone using the number on the form.

To discuss any problem sending back a tax review form P810, contact the tax office detailed on the front of the form.

Self-assessment is a system for collecting tax from people outside the PAYE system or where extra tax is due on top of the amount collected through PAYE.

If you’re self-employed or have complicated tax affairs, you may be asked to fill in a tax return each year. This is a form that gives information about your income and certain types of spending so that your tax bill for the year can be worked out. It can be a paper form or an online tax return. There are strict deadlines for sending back (‘filing’) tax returns. The deadlines are:

• 31 October for paper returns (if you miss this, you have to file online to avoid a fine)
• 31 January for online returns.

If you miss the January deadline or if you send in a paper return after the October deadline, there is an automatic fine of £100, even if you have no tax to pay or have paid the tax you owe. Further fines will be added after three months. There are also set dates for paying any tax you owe, and you’ll be charged interest and penalties if you miss those dates.

You can appeal against fines and penalties but you have to show that you had a reasonable excuse for missing a deadline. What counts as a reasonable excuse depends on the facts of each case, but HMRC say an illness must be so serious that it prevents you controlling your business affairs (for example, a coma or stroke).

If you have a lengthy stay in hospital, HMRC would normally expect you to make arrangements for your tax return to be completed for you. The illness of your partner or a close relative may not be accepted as a reasonable excuse.

For more information, contact the Self-Assessment Tax Helpline on 0845 900 0444 or visit GOV.UK.