However, personal preference has not figured highly in the modus operandi of Iraqi and Saudi insurgents for whom decapitation has become the method of choice for dispatching POWs and collaborators.

Until the shooting dead in June of US soldier Keith Maupin, the insurgents had made a point of beheading their captives and disseminating the grisly scenes over the internet.

Most people would recoil at the mere thought, but experts say that is precisely the aim. In war, ascendancy in the horror stakes can be a major battlefield gain.

"It gives people an enormous feeling of their own power that they can threaten this fate to their opponents," believes Professor Ian Robins, a London-based traumatic stress psychologist who specialises in treating war prisoners.

While it serves as a morale booster for the perpetrators, it has the converse effect on their opponents.

"It's a well thought through strategy. It's exactly the kind of thing that damages enemy morale," said Robins.

"There are several weapons like this which are negligible in terms of pure military value but because they have this extremely horrific aspect their use causes much more damage."

Military ramifications

According to another British psychologist, the act can have far-reaching consequences in the field.

"It's a well thought through strategy.
It's exactly the kind
of thing that damages enemy morale"

Professor Ian Robins,
London-based traumatic
stress psychologist

"It is a very effective arrow in the heart of the opposition. If a soldier knows that if he gets captured he is not coming back, it may induce him to freeze on the job or to make mistakes," Simon Meyerson told Aljazeera.net.

The captive himself becomes a weapon for his captors, a tool for the transmission of horror to the rest of the enemy, effective in proportion to the level of his fear.

"They very quickly fall into one of two groups; those whose minds and emotions freeze and who stay emotionless, and those who go into a state of terror and disintegrate losing all emotional structure and defiance," he added.

While South Korean captive Kim Sun-il reacted by breaking down and pleading desperately for his life, US freewheeler Nicholas Berg appeared calm and resigned to his fate.

But Meyerson cautioned that in some cases the horror might be counter-productive in inciting the opposition to similar brutality.

The act also gives insurgents another advantage. In an age where wars are fought as much on TV as on the battlefield, they no longer need actual victories. The battle, says Meyerson, can be "won with a single dramatic visual impact".

Political success

It is at this political level that the tactic has earned insurgents their greatest success. While big exchange demands such as the cancellation of troop deployments or mass prisoner releases have been rejected, more modest aims have been realised.

Keith Maupin's killing generated
much less publicity than Berg's

This week two Turkish workers being held in Iraq were freed after their company promised to stop working for US forces.

Across the Arabian Gulf strife-stricken Saudi Arabia is witnessing an exodus of skilled western expatriates following a wave of killings by insurgents aiming to end what they see as foreign plunder of their country.

In South Korea, the capture of Kim Sun-il brought thousands of people on to the streets to protest the planned deployment of 3000 troops in Iraq.

Public opinion

By turning his family into celebrity anti-war campaigners the beheading of Berg became a political gain for his killers.

"The acts are a sure way of making governments look incompetent by showing they are powerless to stop them despite the fact that they might pour billions of dollars into the campaign," said Professor Robins.

Nothing succeeds like success and so long as the acts continue to put pressure on enemy governments there is little incentive for the perpetrators to stop, according to Robins.

"Behaviour is maintained or increased by its consequences. This [beheadings] gets an enormous amount of attention and scrutiny and therefore it is highly likely it will continue."

If current reports that US marine Wassef Ali Hassoun has been beheaded turn out to be true, it would underline the point.