THEY call it an "asymmetric" threat – an enemy disguised among the population who can strike 24/7 in wildly unpredictable ways, writes Lyn Barton reporting from Afghanistan.

It can be disorientating, sapping of the strength and astonishingly difficult to deal with. But not impossible.

For the last five months, 3 Commando Brigade, predominantly made up of South West units and troops, has been fighting the war in Afghanistan in the Taliban's own backyard, the notorious Helmand province.

Many of the thousands of men and women fighting and living here are now entering the last few weeks of their tour.

"Home" is something real and at hand, so it is perhaps no surprise so many tanned faces look battle weary and perhaps slightly jaded – like tired tourists whose greatest wish is to collapse into their own beds.

But, says Major Marcus Taylor, of Chivenor-based Commando Logistic Regiment (CLR), there is no question of scaling down activities.

"The threat is persistent. The Taliban do not have an end-of-tour date. Our men and women are professional and highly trained. Of course they are looking forward to going home, but there is no way they will let that influence their actions.

"They will continue to do their job until the very last moment."

The regiment has spent the tour in Camp Bastion, the heart of Battlegroup South's campaign to restore law and order to Afghanistan. One of its primary duties is to ensure front-line Forward Operating Bases (FOB) and Patrol Bases (PB) are stocked with everything from bullets to beds.

This means forming long, agonisingly slow-moving convoys of up to 100 vehicles threading their way through the desert. It puts men and women directly in the line of fire. "Every patrol gets hit, sometimes two or three times," said Major Taylor.

"Since we have been here, we have had 14 mine strikes while on patrol, the regiment has also suffered two killed in action and there has been one surgical case."

Territorial Army soldiers, based all over the South West, are also helping to provide security with the 6 Rifles regiment operating patrols in the region. The 6 Rifles has headquarters in Exeter with TA bases in Taunton, Truro, Gloucester and Dorchester.

They carry out a number of tasks in the surrounding areas of Camp Bastion, including providing helicopter protection for the Medical Emergency Response Team (MERT) who fly out to injured soldiers.

British troops are operating in this inhospitable, landlocked country as part of the International Security Assistance Force (ISAF).

But in the face of overwhelmingly superior firepower, air supremacy and ISAF military spend worth millions, the Taliban are refusing to give up.

It demonstrates a spirit which must be acknowledged, said Major Taylor.

"You need to have respect for the Taliban," he added. "They're cunning, adaptive and in most areas, they know the ground better than you do.

"They do not conform to any of the norms of warfare. It is a classic insurgency where they are among the local population.

"The modern word is that it is an example of an 'asymmetric' threat – they can attack in any way at any time. They even recruit 13-year-olds to act as suicide bombers.

"It is difficult to defend, let alone even understand, suicide bombers."

In the five months since starting their tour, 3 Commando has scored some headline-grabbing victories.

Earlier this week, details emerged of Operation Diesel, which saw Royal Marine Commandos succeed in smashing a drug factory and seizing millions of pounds of opium and chemicals to make narcotics.

Under the media radar and away from the gunfire, there has been the steady hum of reconstruction work, part of the continuing battle to win the hearts and minds of Afghan people.

In villages across the region, people who once ran for their lives, as they were caught in the crossfire between Taliban and ISAF forces, are now returning to their compounds.

Schools are being built, the patchy healthcare provision is being supported and farmers are going back to their ploughs – although the efforts to wean them from a harvest of poppies are still tricky.

At Camp Bastion, in the middle of the desert, there are signs of the relentless expansion that was promised.

Contractors are on site, improving accommodation and even installing wi-fi Internet access.

Away from the relative comforts of Bastion, the battles have been hard with conditions during Afghanistan's winter often as Arctic as the summer is boiling.

As the tour comes to an end, the totting-up is under way and the tally is impressive, with hundreds of insurgents killed, millions of pounds of drugs seized and people blighted by decades of war allowed to get on with their lives peacefully.

There is no doubt victories have been purchased and there is no doubt the price has been high – 145 lives lost since 2001 and 30 during this tour.

For many, the question only time can provide an answer to is whether it has been a price too high.