The Royal Bank of Scotland has revealed that it was involved in international tax avoidance schemes that cost British and US treasuries £500m in lost revenues, The Guardian reports. Such practice which is known as 'structured trades' tied up £25bn, which allowed RBS to make negotiations across national borders in order to take advantage of tax laws in different countries. Sir Fred Goodwin, former chief executive of RBS, oversaw deals in places including the Cayman Islands and Carribean. The new management of RBS will stop structured trades from being made now that it recognises that the bank is 70% owned by the tax payer. According to The Guardian an RBS source said: 'We have always sought to avoid this sort of stance and that's more important now than ever. It's not a sustainable way to do business.'