Is that a bug under your boardroom table?

The news that Michael Howard, the former leader of the Conservative party, is to become the European chairman of Diligence, a US-based corporate intelligence company, is the latest sign of gentrification in a sector that was once seen as the preserve of shifty types who rifle through bins under cover of darkness.

There is still a role for that sort of operator, but as the commercial investigation game gets serious, a growing number of private investigators have a background in investment banking or the law. Indeed, one security industry analyst, Equitable Services, has predicted that the global private security market could be worth £150 billion by 2010, fuelled by mushrooming demand for high-quality commercial intelligence.

As more and more billionaires emerge from the Middle East and Eastern Europe, for example, there is a corresponding need for forensic analysis of the source and stability of their wealth. And companies such as Kroll Associates, Control Risks, Risk Advisory, GPW and even Pinkertons, the venerable American private detective agency, are prospering as never before. Kroll alone is said to have a turnover of $1 billion.

As the quarry becomes increasingly sophisticated, so the investigators are trading up. Diligence, the firm that Howard is joining, was founded in 2000 by a small group of ex-CIA and MI5 officers; it is chaired by Richard Burt, a former US ambassador to Germany. The careers page on its website provides a neat illustration of the way the corporate surveillance industry is going. ‘While our staff include many people with extensive governmental and business backgrounds,’ it says, ‘we are actively recruiting young and mid-career professionals — from intelligence, journalism, business and finance — who want to build exciting careers in this burgeoning new space.’ The employee featured on the home page is Nada Bouari, one of Diligence’s project managers; a former investigator with the Volcker Commission, she specialises in fraud and compliance issues, and is fluent in French and Arabic.