We take it for granted that the state should have a monopoly on the use of violence. Previous generations, however, were more relaxed about private-sector involvement in the bloody business of war.

‘Persians, Greeks and Romans all relied on hired muscle, to the extent that the Persian victory over Egypt at the Battle of Pelusium in 525 BC saw both sides field armies largely consisting of Greek mercenaries,’ Stephen Armstrong writes in this breezy canter through the recent history of guns for hire.

For much of the Middle Ages, European battlefields were the playgrounds of condottieri, puffed-up mercenary captains such as Sir John Hawkwood and Sigismondo Malatesta hired by Italian city-states to wage war.

The tradition persisted into the 19th century. Many of the troops Wellington mustered at Waterloo in 1815 were mercenaries.

Armstrong kicks off his story with the mercenary renaissance of the 1960s and the story of dashing David Stirling, founder of the Special Air Service.

Had it not been for Stirling and the British Mercenary Organisation, royalist forces in Aden would likely have collapsed under the onslaught of Nasser’s invasion in 1962.

In 1967, having embarked on a profitable business connection with King Faisal of Saudi Arabia, Stirling founded Watchguard International, the world’s first private security company. The Brits have been well represented in private security ever since.

Fast-forward to the second Gulf War in 2003. Much of the battlefield was by now a privatised business.

KBR (Kellogg Brown and Root), formerly a subsidiary of the Halliburton corporation, provides everything from accommodation, laundry and linens to vehicle maintenance, military canteens and convoys.

Private-security companies, most of them British and American, mushroom to fill the sudden demand for convoy protection, bodyguarding and armoured taxi services. Some are good. Others, such as Custer Battles and Triple Canopy at the cowboy end of the market, are not.

By the end of Donald Rumsfeld’s tenure as Secretary of Defense in 2006, there were 100,000 contractors in Iraq, a ratio of one to one with American troops.

With 14,000 personnel in uniform in early 2008, the British security company Erinys has more men in Iraq than the British Army. The work is dangerous, but the money is good.

From an Iraqi perspective, the arrival of large numbers of pumped-up young men with goatee beards who look as though they are dressed for a paramilitary catwalk, has been an unwelcome development.

Armstrong quotes an eyewitness describing the deployment of a security team from Blackwater, the American company awarded a $27.7 million no-bid contract to provide security for the American viceroy Paul Bremer.

‘The guards were chiselled like bodybuilders and wore tacky, wraparound sunglasses. Many wore goatees and dressed in all-khaki uniform with ammo vests or Blackwater T-shirts with the company’s trademark bear claw in the cross hairs, sleeves rolled up.

“Their haircuts were short, and they sported security earpieces and lightweight machine guns. They bossed around journalists and ran Iraqi cars off the roads.’

And, he might have added, hurled mineral water bottles into the windscreens of innocent Iraqi drivers and screamed, ‘F—ING BACK OFF!’

It is this sort of behaviour and character – physically ludicrous, overconfident, culturally insensitive and intellectually challenged – that gives the private security industry such a poor reputation.

Armstrong’s original inspiration for this book came from the disgraceful shooting by a Blackwater team of 16 Iraqi civilians in Baghdad last September.

Blanket immunity, guaranteed by Bremer in one of his last acts in Iraq, is not the best way to deal with this problem of perception.

Armstrong quotes lengthy conversations with Lieutenant Colonel Tim Spicer, founder of the British group Aegis, which at one point had the world’s largest security contract in Iraq.

The story of Aegis, for whom this reviewer established a nationwide civil affairs programme in Iraq, demonstrates how effective a modern private security company can be in a dangerous environment where aid agencies and humanitarian organisations are simply unable to operate.

Whatever one thinks about it, Spicer argues the private security industry is here to stay and there is little reason to doubt it.

Darfur crops up repeatedly here. Frustrated at the unwillingness and inability of sovereign states to supply sufficient troops to the UN/African Union peacekeeping mission, the actress Mia Farrow recently called for a private-sector response, suggesting that Blackwater should intervene.

Spicer envisages a future conflict in a failed state when the UN will debate interminably while the bodies pile up, the international community will wring its hands and eventually a private company will be legally contracted to assist.

As he puts it, ‘Which is worse? Dead babies or a private company?’

Far-fetched? Perhaps not. In 2005, Blackstone launched Greystone, a subsidiary company designed to put a military force into the field – quickly.

In the company’s own words: ‘The Greystone peacekeeping solution provides a flexible force with the ability to provide a properly trained force in a short period of time. The force provides a light infantry solution that is self-contained and self-sufficient. The Greystone peacekeeping programme leverages efficiency of private resources to provide a complete cost-effective security solution.’

Given Khartoum’s hostility to the West, tackling Darfur might be a little optimistic at this stage. Providing a ‘solution’ to lazy corporate jargon would be a good start.

We take it for granted that the state should have a monopoly on the use of violence. Previous generations, however, were more relaxed about private-sector involvement in the bloody business of war.

‘Persians, Greeks and Romans all relied on hired muscle, to the extent that the Persian victory over Egypt at the Battle of Pelusium in 525 BC saw both sides field armies largely consisting of Greek mercenaries,’ Stephen Armstrong writes in this breezy canter through the recent history of guns for hire.

For much of the Middle Ages, European battlefields were the playgrounds of condottieri, puffed-up mercenary captains such as Sir John Hawkwood and Sigismondo Malatesta hired by Italian city-states to wage war.

The tradition persisted into the 19th century. Many of the troops Wellington mustered at Waterloo in 1815 were mercenaries.

Armstrong kicks off his story with the mercenary renaissance of the 1960s and the story of dashing David Stirling, founder of the Special Air Service.

Had it not been for Stirling and the British Mercenary Organisation, royalist forces in Aden would likely have collapsed under the onslaught of Nasser’s invasion in 1962.

In 1967, having embarked on a profitable business connection with King Faisal of Saudi Arabia, Stirling founded Watchguard International, the world’s first private security company. The Brits have been well represented in private security ever since.

Fast-forward to the second Gulf War in 2003. Much of the battlefield was by now a privatised business.

KBR (Kellogg Brown and Root), formerly a subsidiary of the Halliburton corporation, provides everything from accommodation, laundry and linens to vehicle maintenance, military canteens and convoys.

Private-security companies, most of them British and American, mushroom to fill the sudden demand for convoy protection, bodyguarding and armoured taxi services. Some are good. Others, such as Custer Battles and Triple Canopy at the cowboy end of the market, are not.

By the end of Donald Rumsfeld’s tenure as Secretary of Defense in 2006, there were 100,000 contractors in Iraq, a ratio of one to one with American troops.

With 14,000 personnel in uniform in early 2008, the British security company Erinys has more men in Iraq than the British Army. The work is dangerous, but the money is good.

From an Iraqi perspective, the arrival of large numbers of pumped-up young men with goatee beards who look as though they are dressed for a paramilitary catwalk, has been an unwelcome development.

Armstrong quotes an eyewitness describing the deployment of a security team from Blackwater, the American company awarded a $27.7 million no-bid contract to provide security for the American viceroy Paul Bremer.

‘The guards were chiselled like bodybuilders and wore tacky, wraparound sunglasses. Many wore goatees and dressed in all-khaki uniform with ammo vests or Blackwater T-shirts with the company’s trademark bear claw in the cross hairs, sleeves rolled up.

“Their haircuts were short, and they sported security earpieces and lightweight machine guns. They bossed around journalists and ran Iraqi cars off the roads.’

And, he might have added, hurled mineral water bottles into the windscreens of innocent Iraqi drivers and screamed, ‘F—ING BACK OFF!’

It is this sort of behaviour and character – physically ludicrous, overconfident, culturally insensitive and intellectually challenged – that gives the private security industry such a poor reputation.

Armstrong’s original inspiration for this book came from the disgraceful shooting by a Blackwater team of 16 Iraqi civilians in Baghdad last September.

Blanket immunity, guaranteed by Bremer in one of his last acts in Iraq, is not the best way to deal with this problem of perception.

Armstrong quotes lengthy conversations with Lieutenant Colonel Tim Spicer, founder of the British group Aegis, which at one point had the world’s largest security contract in Iraq.

The story of Aegis, for whom this reviewer established a nationwide civil affairs programme in Iraq, demonstrates how effective a modern private security company can be in a dangerous environment where aid agencies and humanitarian organisations are simply unable to operate.

Whatever one thinks about it, Spicer argues the private security industry is here to stay and there is little reason to doubt it.

Darfur crops up repeatedly here. Frustrated at the unwillingness and inability of sovereign states to supply sufficient troops to the UN/African Union peacekeeping mission, the actress Mia Farrow recently called for a private-sector response, suggesting that Blackwater should intervene.

Spicer envisages a future conflict in a failed state when the UN will debate interminably while the bodies pile up, the international community will wring its hands and eventually a private company will be legally contracted to assist.

As he puts it, ‘Which is worse? Dead babies or a private company?’

Far-fetched? Perhaps not. In 2005, Blackstone launched Greystone, a subsidiary company designed to put a military force into the field – quickly.

In the company’s own words: ‘The Greystone peacekeeping solution provides a flexible force with the ability to provide a properly trained force in a short period of time. The force provides a light infantry solution that is self-contained and self-sufficient. The Greystone peacekeeping programme leverages efficiency of private resources to provide a complete cost-effective security solution.’

Given Khartoum’s hostility to the West, tackling Darfur might be a little optimistic at this stage. Providing a ‘solution’ to lazy corporate jargon would be a good start.