Mark Townsend visits the marksmen about to be deployed on the front line and asks them about the psychology of killing.
In the moments before he pulls the trigger, Dean has learnt to switch off. No longer does the 28-year-old sniper register the close-up face caught in the centre of his crosshairs. "It's about getting into your bubble, focusing on the act until it becomes automatic, repetitive. You concentrate only on the shot," said the Coldstream Guards colour sergeant. Like all army snipers, Dean does not disclose his surname for fear of his family becoming a target for home-grown extremists. Within modern warfare and its array of laser-guided missiles and smart bombs, only men like Dean regularly see their victims at the point of death.
Snipers are playing an increasingly important role in Helmand province in Afghanistan where 8,100 British soldiers are stationed. Scores of Taliban have been shot dead. One sniper alone is reported to have killed 39 of the enemy. Dean, who spent six months in Helmand last year, would not talk about his "kill tally", but admitted that colleagues routinely accounted for "handfuls" of the enemy.
Snipers are becoming an increasingly valued weapon in the desert of Helmand. "We're starting to see a definite renaissance of sniping," said Frank, a captain and commanding officer of the sniper division at the Land Warfare Centre in Wiltshire.
Sniping's tactical comeback is facilitated by mounting concern over the number of civilian casualties in southern Afghanistan caused by air strikes. Fears over the risk of collateral damage from jets are bolstered by field reports indicating that snipers are the military's most cost-effective, discriminating fighting machine in Helmand.
A report by Civic - the Campaign for Innocent Victims in Conflict - will this week corroborate concern over collateral damage by confirming a record death toll of Afghan civilians last year. However, Civic's Sarah Holewinski said they had no evidence or reports of British snipers mistakenly targeting innocent Afghans and hoped that the "planning going into sniper use remains thorough and sound".
At the Wiltshire training base, courses are heavily oversubscribed. More than 240 soldiers are vying to be selected for the 120 places a year. In Helmand itself there are 25 snipers seeking to engage "high-value targets" such as Taliban commanders or individuals identified as linked to al-Qaida. The armed forces have 330 trained snipers at present, more than double the total during the 1990s, when sniping was wound down.
Sniping is a form of psychological warfare. Shots from an invisible source can, according to the Ministry of Defence, induce terror in advancing forces; even tank commanders cower inside from an unseen but precise foe. Yet the real mental duel is contested within the sniper's mind. Its practitioners know that, when they squeeze the trigger, the object of their concentration will die.
Frank looks for recruits whose minds are sufficiently robust to concentrate on their mission rather than the human being within their sights. "It is one thing to kill in the heat of the battle when the blood's up, but it's quite another when you have a lot of time to think," he said. "You need to get the right man for the job in case he hesitates or is going to suffer problems down the line."
A calm, composed disposition is a prerequisite. As is patience: snipers can spend hours motionless as they wait for the optimum time to strike. Psychological profiling remains critical in selecting the right candidates; any detection of mental fragility and they are out, says Frank.
The act of shooting itself is a lesson in deliberation. The body must be perfectly still, the breathing controlled. Last week Dean targeted a "simulated head" 400m away across a snow-smothered Wiltshire field. Through the scope of his LII5A3 sniper rifle, the head's two-dimensional features were as clear as if it were sited across a room. Steadily Dean positioned the target into the centre of the mildot reticule, its crosshairs. The headshot is preferable and invariably fatal. But to shoot a bullet in the heat of Afghanistan, first a sniper must ascertain the wind speed, temperature, barometric pressure and humidity at the target.
Many snipers hail from farming communities, men who developed an early interest in hunting and creeping after prey undetected. "It's about stalking; we are looking for that natural hunting ability, looking for a cut above the rest," said Frank.
Snipers must also be comfortable in their own company for days on end as they operate undercover behind Taliban lines. The enemy cannot be allowed to identify their position. It is one thing to kill, but to kill again snipers must be able to retreat without enemy forces pinpointing them.
But, above all, Frank's team must train a sniper to obliterate all distractions; training is deliberately repetitive to make sniping an instinctive process. Any potential psychological effects are addressed at post-operation debriefs under the specialised risk management scheme with help specially tailored to address the unique strains of sniping. Its effectiveness is unknown; there are no data available to measure whether snipers sustain more psychological trauma than, say, infantrymen.
Another factor driving the resurgence of sniping is cost-effectiveness. During the Vietnam war, the average number of rounds expended per kill with M-16 rifles was 50,000.
By contrast, snipers averaged 1.3 bullets per kill, and defence officials estimate that contemporary trends are likely to mirror the ratios recorded in Indochina.
Each of the 8.59mm bullets used by UK snipers in southern Afghanistan costs about £20, compared to a single projectile from the Javelin anti-tank missile, which costs £70,000.
They were pinned down on a small hill just east of Kajaki, northern Helmand, a company of Royal Anglian Regiment infantrymen surrounded by Taliban firing from 21 positions. Amid the chaotic firefight, a lone figure crawled along an exposed ridge and, Lambert and Butler cigarette drooping from his bottom lip, slowly took aim. Over the next 15 minutes, the British sniper methodically eliminated seven of the Taliban gunpoints.
The sniper never said a word, but single-handedly ensured his colleagues made a successful dawn retreat one August morning in 2007, a single example among countless occasions when snipers have underlined their value in Afghanistan. A Royal Marines spokesman said: "Once you have targeted the Taliban, you can run down their numbers pretty quickly; without a doubt, sniping is a battle-winner." He recalled one occasion when a sniper picked out Taliban gunmen 1,800m away, a spot that also helped save lives. Only days after the Kajaki sniper's heroics 18 months ago, a 500lb bomb from an American fighter killed three British soldiers in the same location, an illustration of the risks inherent in high-speed air strikes and a tragedy that advocates of sniping still refer to.
As the Afghan conflict rumbles on, military experts predict the role of the sniper will become increasingly central. The Pentagon is developing a guided smart bullet for use in sniper rifles. In the future, men like Dean may crouch four miles away from their target before sending a smartslug to destroy a distant, faceless foe.