Yes, you may need to.
If you are a UK taxpayer selling resources through TES, you will need to submit a tax return.
If you have not received a notice to file a tax return from HMRC, you need to register for self-assessment by 5 October following the end of the tax year.
The tax year runs from 6 April to 5 April each year (for example, 6 April 2014 to 5 April 2015 is referred to as Tax Year 14/15). In your self-assessment tax return (form SA100), you need to include how much you earned in royalties in that tax year.
You can complete a paper copy of your tax return or submit it online on the HMRC website. HMRC recommend doing the return online, as they do the tax calculations for you and on-screen help is available.
Remember, to file a tax return online, you need an HMRC Gateway account, which may take a few weeks to be set up, so do allow enough time to do this and meet the filing deadline.
The information contained in this section will help you think about the tax implications of selling you content on TES Resources. However, we are not tax advisors and recommend that you consult a tax professional to get more advice about your own specific circumstances.