One of the Conservative Party's biggest donors and a billionaire hedge fund manager who played a key role in the Brexit campaign are both braced for revelations about their financial affairs, The Telegraph can disclose as a second company is revealed as a victim in the offshore Bermuda hack.

Lord Ashcroft, who has given millions to the Tories, could see his company's financial deals exposed as he is a client of a company which has been caught up in a huge data leak.

The dealings of Robert Mercer, a major donor to Donald Trump who also aided the Leave.EU campaign, could also come under scrutiny following the attack on one of the world's biggest offshore law firms.

The men are the first to be named in connection with hack on Appleby, first disclosed by The Telegraph, files from which are expected to be published by an international group of left-leaning journalists on Sunday.

The news that Lord Ashcroft could be among those named will be potentially embarrassing to the Conservative party because of sensitivities surrounding legitimate off shore tax avoidance schemes. The leak comes a year after the "Panama Papers" exposed the hidden millions of politicians, celebrities and some of the world's richest businessmen.