The company remembered by Brits of a certain age (in its Group 4 Securicor guise) for 'losing' a couple of prisoners en route to chokey is the product of numerous merger deals stretching back over the years. Its oldest constituent is a Danish security-guard outfit called Falcke, founded in Copenhagen in 1901. Falcke in turn merged with the Belgian Group 4 in 2000.
The British side of the story, Securicor, began life as Nightwatch Services in 1935, the brainchild of former Liberal Home Secretary Edward Shortt. He took his inspiration from the Boys in Blue - his original four employees wore old police uniforms and rode bicycles.
Securicor built itself a nice line in guarding factories and transporting cash for banks and company payrolls, becoming a FTSE 100 member in the process. In 2004, Group 4 Falcke merged with Securicor to become Group 4 Securicor, then G4S.
The rise in public sector outsourcing over the past two decades has been the making of G4S. Thanks to a willingness to take on everything from CCTV monitoring in shopping centres to prisons and border security, it turned over £7.4bn in 2010. Operating in 125 countries, it provides security guards to the US government in Iraq and Afghanistan, and, of course, 10,000 guards for the Olympic Games in London this summer - a deal worth £200m.
Last year, it hit the headlines for its attempted £5.2bn takeover of Danish support services outfit ISS, which would have created a global outsourcing giant to take on Serco, Capita et al. But after being trumpeted as a done deal, it fell through for lack of shareholder support. Ouch.
Who's the boss?
Essex boy Nick Buckles has been in the hot seat since 2002, overseeing the deal with Group 4 and 70 other acquisitions since. He joined Securicor in 1985 as a project accountant and on his watch G4S has grown to be the largest employer on the London Stock Exchange.
What's the secret formula?
G4S's readiness to tackle pretty much any security-related task - even those involving hefty political or reputational risk - has endeared it to governments and shareholders alike over the years. But after ISS, its diversify-and-grow strategy seems to have hit the buffers.
Don't mention ...
Bonuses. Buckles opted not to accept a £750,000 bonus last month after it emerged that the ISS debacle cost G4S £55m in fees. So the bankers and assorted advisers did well out of a deal that never came off. Snouts in the trough, anyone?
Net profit: £245m
2010 figures (Source: G4S annual report)