Control Risks, which provides security for foreign companies in Iraq and the British Government, is poised to join the bidding war for Wall St's favourite detective agency, Kroll.

The security firm, headed by Richard Fenning, is linking with US private equity firm General Atlantic to table a £600 million ($1.3 billion) bid. Additional firepower for the bid could come from British private equity group 3i, which has a 17 per cent stake in Control Risks.

Control Risks was founded in 1975 by former army officer Timothy Royle to provide advice to insurer Hogg Robinson after a spate of kidnappings of company executives in the US and Europe by political extremists. It became independent in 1982 and offers advice on the political, economic and logistical risks of doing business abroad as well as providing crisis-management services. A large contract with the British Government for work in Iraq accounted for 30 per cent of its sales in 2008.

The firm has more than 1000 employees in 15 countries and performs vetting, provides bodyguards and carries out anti-stalking measures for high-profile individuals. The majority of its clients are large corporations that need political and security risk assessments.

Control Risks rose to prominence in 1997 when it produced video evidence of senior Co-operative Wholesale Society executives passing information about the group to British entrepreneur Andrew Regan ahead of his planned bid for the business. But it has also grown on the back of the increase in global mergers and acquisitions activity and rising use of technology in the workplace.

"Investigating technology-based fraud and providing political and economic analysis for entrants to a particular market remains its stock in trade," said one security analyst.

Kroll is best known for helping to uncover the hidden assets of Saddam Hussein, and for proving that the death of "God's banker", Roberto Calvi, found hanging from London's Blackfriars bridge in 1982, was not suicide.

In the early 1980s, Kroll started investigating corporate raiders such as Sir James Goldsmith and Victor Posner on behalf of the companies they were attacking. During the 1990s, it also gained attention for its success in searching for assets hidden by dictators Jean-Claude Duvalier of Haiti and Ferdinand and Imelda Marcos of the Philippines.

Following the September 11 attacks in 2001 and a rash of corporate scandals during the early part of the decade Kroll and other corporate security groups were in increasing demand.

However, Kroll has seen many twists and turns in its history as it pursued diversification into other areas such as computer security, forensic accounting, data recovery, employee screening and restructuring.

Kroll has offices in 33 countries and employs more than 3800 people. By 1987, it had established a reputation as Wall St's pre-eminent private eye during hostile takeovers, after being hired to look into the new breed of financiers and their novel means of raising money. Kroll was hired by Sears Tower in Chicago to review security after September 11 and took the job of restructuring Enron, brought down by fraud in 2001.

City sources say Control Risks and General Atlantic face fierce competition for Kroll from three American private equity bidders - Carlyle, Apax and BC Partners - with the latter teaming up with restructuring expert David Buchler.

Kroll has been put up for auction by parent company Marsh & McLennan, the global insurance broker and consultancy company which acquired the firm from founder Jules Kroll in 2004 for nearly US$2 billion ($2.85 billion).

Carlyle is viewed as a leading contender for the business as it has historically had a strong focus on the defence and security sectors. But General Atlantic has deep pockets - the firm has around US$15 billion of capital under management and is among the 50 largest private equity firms globally.