Former world number one tennis player Andre Agassi has won his appeal against a high court ruling that athletes and other professional entertainers are liable to tax on sponsors' payments while working in Britain.

The Court of Appeal in London on Friday upheld the 33-year-old American's argument that he should not be taxed as neither he nor his sponsors were based in Britain.

Although permission to appeal to the House of Lords was refused, lawyers for the Inland Revenue indicated they would apply directly to the Law Lords to challenge the decision.

The battle is seen as test case for similar sporting and entertainment figures with an estimated 500 million pounds ($928.7 million) at stake. The figure in Agassi's case is just over 27,000 pounds ($50,000).