Cash for access: Secretive businessman Fares Fares gave £227,000

But of all the wealthy tycoons and Tory peers to grace the list of donors invited to dinner with David Cameron, Fares Fares is one of the least well known.

The 42-year-old and his wife Tania have donated £227,000 to the Conservative Party since 2009.

The son of Issam Fares, the former deputy prime minister of Lebanon, he is certainly well-connected. He was schooled at Harrow, then went on to graduate from Tufts University in Massachusetts in 1992.

An online biography reveals that he founded the Fares Lecture Series, which brings world leaders to discuss challenges facing the Middle East and whose past speakers include Baroness Thatcher and Bill Clinton.

Mr Fares went on to join the investment firm Oppenheimer & Company in New York, working in the corporate finance department, before founding Wedge Alternatives, a financial investment firm.

Described as British by Companies House, Mr Fares is also a director and vice-president of Wedge Group, his father’s company, overseeing a portfolio of investments for the wealthy and influential businessman.

The company, based in Houston, Texas, states on its website that under his tenure, since 1995, the firm helped build Pioneer Drilling, an onshore contract driller, as well as leading various other acquisitions.

Mr Fares also serves as a director of the East West Institute and on the boards of numerous private companies and charitable foundations. He and his Lebanese-born wife began their married life in Houston before moving to London in 2002, where they live in a £10.3 million property in Kensington.