The use of tax havens by rich UK residents is costing UK taxpayers at least £4bn a year, research has revealed. Jersey, Switzerland, the Isle of Man and Guernsey cause the highest loss of UK taxes, according to a study published by TUC, which is the first analysis into the role of individual tax havens in tax lost to the UK. Under the EU's Savings Tax Directive, UK residents who have offshore bank accounts in tax havens have the choice of declaring all their interest to HM Revenue & Customs or choose to have 15% tax withheld from the interest payments by the tax haven where they hold their account. Three-quarters of this is then paid to the UK government with the rest being retained by the government of the tax haven. Under such rules, this puts the UK tax rate on these offshore accounts at 11.25%, as opposed to the 40% that would be paid if the money was held in the UK, during the period the research covers. TUC general secretary Brendan Barber said: 'The mechanisms of tax avoidance are always hard to understand, but this is a very simple story. If the super-rich held their money and assets in the UK they would contribute at least £4bn extra.' The research comes at the same time that the Liberal Democrats are calling for an independent review into the use of tax havens by British banks that have been bailed out by the Treasury.