This form of trading is liable to full capital gains tax and stamp duty. Why Britain is not a better option. All countries and governments twx their own online gambling tax policies and legislation so we need to look at this question from a global perspective. How To Bet Guide: From Beginners to Professionals. Do you have to pay tax on your gambling winnings?Gambling may be a profitable industry, but there are only a number of companies that are doing so well that they can afford to pay the 15 % tax and get a UK license. And yes, most of these firms have a solid customer base in Britain. Online gambling companies ponder future as UK gov’t confirms 15% POC tax rate. BY Steven Stradbrooke ON August 16, Online betting companies serving customers in the United Kingdom will be required to pay 15 % tax on the gross profits they generate from those customers. UK Gambling Taxes. Key Points: All winnings either online or offline are tax free! Any betting tax abolished in by Gordon Brown. Tax used to be on bookies but they passed to punters. Bookmakers must now pay 15 % POI tax but not punters.