Amber Rudd’s business career has come under scrutiny following a Guardian investigation that reveals her involvement with two companies in an offshore tax haven, and another where her co-director was jailed for fraud.

A fresh leak of tax haven data names the home secretary as having been a director of two companies in the Bahamas – a fact she did not refer to earlier this year when defending David Cameron over his father’s investment fund in the same country.



The Guardian has also discovered new details about her previous career in venture capital during the boom and bust 1990s. One enterprise led her to become a co-director of Monticello, a company that was at the centre of a share ramping investigation.

She was also involved in a company prospecting for diamonds in Siberia that was traded on a notoriously unregulated stock exchange.



Rudd said that her career in business prior to politics was public knowledge but declined to answer questions, including whether she had invested in the Bahamas companies or whether either company had paid tax in the UK.

A rising star of the Conservative party, Rudd has provided scant details about her career before she became an MP in 2010.



Though there is no suggestion she was involved in any wrongdoing, the disclosures may cause her some embarrassment, particularly as pressure grows to crack down on tax avoidance and governments demand more transparency from offshore regimes.



The home secretary’s name appears in a cache of company data from the Bahamas, a Caribbean tax haven that imposes no income, corporate or wealth taxes on individuals investing in offshore companies.



The data, leaked to the German newspaper Süddeutsche Zeitung and shared with the International Consortium of Investigative Journalists, constitutes a list of directors of 175,000 Bahamas registered companies.



The files name Rudd as having been a director of two Bahamas companies, Advanced Asset Allocation Fund and Advanced Asset Allocation Management, between 1998 and 2000.



Records at Companies House also identify her as a director of Monticello plc, which became the centre of an investigation into share ramping after one of her co-directors, Mark O’Hanlon, gave an interview in January 2000 in which he made false claims about the company’s prospects.

Monticello’s share price subsequently skyrocketed and trading on its shares was suspended. Rudd resigned as a board member five months later, two days before she also resigned as director of Advanced Asset Allocation Management.



The episode led the Department of Trade and Industry to investigate, and in 2007 O’Hanlon was convicted of making a false statement and sentenced to 18 months’ imprisonment. He was jailed again in June 2013 following an unrelated fraud conviction.



Prior to Monticello, Rudd was involved in a number of other ventures. The Guardian can disclose she was:



The executive director of Kensington Resources, a company headquartered in Mayfair in London that financed diamond prospecting in Saskatchewan, Canada.

Appointed president in 1994 of another mining company, Siberian Pacific Resources Inc. Rudd raised 500,000 Canadian dollars for a joint venture with a group of Russian geologists searching for diamonds in Siberia.



A director of The Zinc Corporation plc, a company exploring a new technique for zinc extraction. In 1997 the company hoped to go public on the lightly regulated stock exchange Ofex. However, the plans were dropped after it misplaced a cheque for £12,500, according to an interview in which Rudd was quoted. Shortly after the company was bought by Monticello.

Shares in both Kensington and Siberian were traded on the Vancouver Stock Exchange, which prior to its closure in 1999 had a reputation for being poorly regulated. A report commissioned by the finance ministry of British Columbia described a small number of successful enterprises “overshadowed by the continuing occurrence of shams, swindles and market manipulations”.

Rudd supported Cameron earlier this year after the Panama Papers revealed the inner workings of his father’s Blairmore fund, which was run from the Bahamas and incorporated in Panama. Although legal, the unorthodox structure resulted in the fund paying no tax in Britain for three decades.



When interviewed on BBC1’s The Andrew Marr Show after Cameron admitted he had previously held shares in Blairmore, Rudd said: “I think the key thing is here that the prime minister and his family paid the correct amount of tax that they were due.”



When asked if she had money in any offshore trusts herself, Rudd replied: “I don’t, no. But I’m pleased to say that all MPs have a very transparent system. They have to disclose their funds, their income, and of course famously a very clear expenses regulatory system.” She did not mention her previous role running a Bahamas fund.



A spokesperson for the home secretary said: “It is a matter of public record that Amber had a career in business before entering politics. Monticello was thoroughly investigated 16 years ago and those who acted wrongly were identified and prosecuted.”

