The hack on one of the world's biggest offshore law firms has spread with offices on the Isle of Man among those targeted.

Appleby has admitted that its offices in six of the world's biggest offshore jurisdictions were hit by hackers.

Details of the finances of the super-rich may have been stolen from Bermuda, British Virgin Islands, Cayman, Hong Kong, Isle of Man and Mauritius, it is understood.

Experts said that among these are the jurisdictions held up as most transparent in the offshore world and all insist that they are subject to strict regulation.

The confidential files, expected to be released by the International Consortium of Investigative Journalists this weekend, will be the first test of that since scrutiny on the sector increased.

The presence of the Isle of Man on the list is likely to cause concern for the Government, which has insisted that it is clamping down on tax evasion and schemes designed to legally avoid tax.

An Appleby spokesman said: "All the relevant authorities have been informed in each jurisdiction."

The company describes itself as a "global organisation" and says that whilst it acts in ten countries it does not have a headquarters.

One of the allegations which it’s claimed has emerged from the papers is that individuals have been dodging tax by importing planes into the EU via the Isle of Man.