This is a question we get asked a lot. A typical scenario would be that someone is employed either full or part-time and they pay tax and national insurance via their employer’s payroll. This person might also do a little bit of work for themselves, for example making and selling crafts or writing articles – do they need to declare this income to HMRC and pay tax on it?
Well, it depends on how much you are earning ‘on the side’. If you are earning less than £1000 a year from work that is not your not normal job then you don’t need to do anything. However, anything over this and you will need to inform HMRC.
For more info: https://www.gov.uk/income-tax