They’re ex-special forces, CIA spooks or Foreign Legionnaires.

They’re fighting insurgents in Baghdad and patrolling government buildings in Afghanistan. And now they’re spying on environmental protestors and policing the 2012 Olympics. They are above the law and independent from government. They are the privatised armies of mercenaries. Meet the private security contractors - a stock-market-listed corporate version of the mercenary. These private soldiers operate their million-dollar contracts from executive boardrooms in London, Washington, Paris and Oslo. With democracies unwilling to see their children die for strategic reasons in foreign lands, these corporate soldiers are part of the last great outsourcing - the privatisation of war.

With an estimated 48,000 private security contractors at work in Iraq alone, corporate warfare is one of the fastest growing industries in the world. Journalist Armstrong’s excellent book looks into how these companies operate.

‘Frightening . . . He has collected some chilling anecdotes about the corners cut by companies who are only interested in profit.’ Metro