Some of the world’s richest people were braced for their financial details to be exposed on Tuesday night after a major offshore company admitted that its computer records had been hacked.

Appleby, a firm based in Bermuda with offices in many tax havens, said it was in the process of warning clients that they may be implicated in a massive leak of sensitive information.

It is understood the leak involves some of Britain’s wealthiest people, who were instructing lawyers and public relations companies in an effort to protect their reputations.

The disclosure of the leak also threatens to call into question the status of several British Overseas Territories which can offer tax benefits to the very wealthy. If questionable activities or conduct are exposed, the British Government is also likely to face searching questions over its oversight of the territories involved.

It is understood that a global consortium of Left-leaning media organisations is preparing to release the information in the coming days.

The leak comes a year after the release of the so-called “Panama Papers”, in which the hidden millions of some of the world’s rich and powerful were exposed. The disclosures led to the downfall of several governments. Among those named in the “Panama Papers” were close associates of Vladimir Putin, the Russian president, and relatives of Xi Jinping, the Chinese leader, as well as Sigmundur David Gunnlaugsson, Iceland’s prime minister, and Lionel Messi, the Barcelona footballer.