A 'side hustle tax' came into force on 1 January aimed at those who sell second-hand goods online or let out their spare rooms. The new measures aim to target people who evade taxes by failing to declare their income to the authorities. Marketplaces including eBay, Airbnb and Etsy will now be required to report what their users earn to HMRC. The crackdown applies to those who earn more than £1,000 a year through online transactions - such as by selling clothes, delivering takeaway food or renting out accommodation. Once a seller exceeds this threshold, they must register as self-employed and file a tax return at the end of the year. It comes after the UK signed up to a global agreement by the Organisation for Economic Cooperation and Development (OECD) that allows tax officials to share information with authorities in other countries. A HMRC spokesperson said: 'Implementing the OECD rules will enable HMRC to exchange information with other tax authorities to access data from platforms based outside the UK quickly and efficiently.' 'The rules will also make it easier for sellers on these platforms to comply [with tax laws] and will help HMRC to detect and tackle tax evasion when they do not.'