You need to register for Self-Assessment with HM Revenue and Customs (HMRC) before you can send them your tax return.

When you register for the first time you’ll get a Unique Taxpayer Reference (UTR) number. If you’re reregistering you need to use the same UTR as last time.

You should register by 5 October following the end of the tax year you need to send a tax return for.  For example, register by 5 October 2014 to send a 2013 to 2014 tax return This way, you’ll have enough time to complete registration before the tax return and any tax is due. You may have to pay a penalty if you register late.

Deadlines for Filing your tax return:

For the 2013/14 tax year which ended 5 April 2014. The main deadlines are:

paper tax returns - midnight 31 October 2014

online tax returns - midnight 31 January 2015

final payment of any tax due - midnight 31 January 2015

Remember there are penalties for late filing of your return - £100 if your one day late rising to as much as £1,000 if your six months late.