The stereotype of the suicide bomber as a disaffected and brainwashed loser has been blown apart by the revelation that some of the suspects in the latest terror attacks are doctors.

However research recently published by a British academic anticipates the emergence of well-educated, successful professionals willing to kill themselves and others for their cause - and puts it down to team spirit.

According to Dr David Stevens, of the School of Politics and International Relations at Nottingham University, the widely held view of the bombers as religious fanatics, vulnerable through youth and poverty, is wide of the mark.

Dr Stevens argues that while religion is rarely absent from the central role, the suicide bomber is also driven on another level by a rational thought process.

"This is the desire to be part of a group that engenders strength and solidarity from strictness, and encourages members to submit totally to the collective aims of the group," he says.

Being part of an exclusive group with very strict beliefs requires intense commitment, and engenders a deep belief in shared experience and self-sacrifice, according to Dr Stevens.

Suicide bombers are thus motivated by a simple cost-benefit analysis, in which the benefits of self-destruction outweigh the cost.

The attractions of intense solidarity do not only apply to fringe Islamic sects, but also to other cults such as the Moonies and the Branch Davidians.

Dr Stevens also argues that, contrary to popular opinion, poverty, isolation and lack of education are not typical features of the bomber profile.

He cites the case of one of the July 7 bombers, Mohammad Sidique Khan, a 30-year-old with a young family of his own and a job working in primary schools with special needs children.

Likewise it is a common misconception that suicide bombers are mentally ill or irrational, Dr Stevens argues - because that would make them a liability to the terrorist groups with which they were involved.

"From purely an organisational point of view, working with deranged individuals is extremely hazardous," he points out. "Even terrorists don't want to work with those who have a death-wish."