UBS, Switzerland's largest bank, has said it will 'vigorously defend itself' against a lawsuit launched against it by three top Rothschild bankers, after they lost money through investing in personal tax shelter on the bank's advice.

UBS confirmed it was being sued by NM Rothschild & Son's deputy chairman, Anthony Alt, the head of UK advisory, Robert Leitato, and joint global investment banking head, Nigel Higgins, after the three bankers lost money on a "highly aggressive tax avoidance" plan that went sour.