The deaths of five paras last week in Afghanistan’s Helmand province made it the bloodiest week for the regiment since the Falklands war in 1982. And the casualties may be a symptom of a riskier approach being pursued by British troops. It is an investment of blood – and we don’t know yet what the return will be.

Privates Daniel Gamble, 22, Nathan Cuthbertson, 19, and David Murray, 19, died in the Upper Sangin Valley at the beginning of last week (their deaths brought the total killed in Afghanistan to 100); their loss illustrates how dangerous the British strategy is. Gamble had spent nine months learning Pashto and was on a “hearts and minds” patrol. He died when he went to speak to an Afghan man who turned out to be a suicide bomber.

As the set-piece battles become fewer and the troops move about among the population, deaths such as Gamble’s will become more common. On Thursday two more paras, Lance-Corporal James Bateman and Private Jeff Doherty, were killed on a routine foot patrol.

Is the bloody British occupation of Helmand province achieving anything? On Monday Des Browne, the defence secretary, claimed the army is transforming Afghanistan’s heartland “from an area of lawless oppression and terrorism to a place of democracy and development”. Is it?

Earlier this year I spent several weeks with British forces in Helmand. A common view among the troops was summed up by a lance-bombardier from the Royal Artillery with whom I spent some time: “We’re here simply to pick up the pieces. We made a mess of this place and we have a responsibility to sort this out, to get things straight.”

It seemed a less lofty goal than that expressed by Browne, but also a more honourable and more realistic statement. When it comes to “sorting out the mess we made”, Britain is fighting to put back together a country that has never recovered not only from the war the West funded against the Russians, and the anarchy that followed America’s toppling of the Taliban government, but also the follies of British commanders’ early actions.

Whatever grinding progress is now being made in Helmand – and there are real grounds for being optimistic – it is hard to argue that its people have been made better off as a result of the war that erupted when British troops first arrived in the province in the summer of 2006.

With thinking derived from the counter-insurgency campaign in Malaya in the 1950s, a careful and modest British plan was in place in 2006 to secure a development zone in the centre of the province to create an “ink-spot” of security within which development – rebuilding schools, roads, hospitals, etc – could take place and from which government influence could spread.

Unfortunately this was not how it happened. Soldiers told me how they were instead sent to remote “platoon houses” across the province. Initially they had only the fighting strength of nine platoons, which was completely inadequate for the fierce onslaught they faced from the Taliban. The ill-equipped British force ended up scattered and pinned down in fixed town-centre locations, living in sometimes unbearable conditions and fighting fiercely.

To beat off Taliban attacks, British soldiers defended themselves by calling in airstrikes and using artillery and mortars to smash urban areas. A T-shirt on sale at Kandahar airport, and worn by some soldiers I met in Helmand, announced membership of the “Taliban Hunting Club”. In Helmand there has been plenty of killing. You can measure the escalation of violence by the bullets and bombs. Successive deployments expended ammunition in ever greater quantities.

The grim truth, soldiers in Helmand tell you, is that much of the bloodshed has been to no effect. Although a central zone of stability in the province has been gradually expanded, whole parts of the countryside have been “cleared” time and again, only for the Taliban to return. Brigadier John Lorimer, a former British commander, bluntly called it “mowing the lawn”. A score card from all of this might read simply: “Many Taliban dead; precious little territory gained.”

This “mowing the lawn” approach unsurprisingly alienated local people. The idea then that the British were creating security to allow development was risible.

If you looked at an honest situation report after two years of bloody fighting in Helmand, it would have to include some heavy negatives: a clutch of towns deserted because of fighting, an opium harvest so vast that some suggest only a lack of fertile land prevents it getting any bigger, an enemy which still roams free in swathes of the cultivated “green zone” by the Helmand River, and an electricity supply to the towns that has got worse. Add to that an alliance with Afghan “friendly forces” who have often proved deeply corrupt.

There is room for optimism, however, and from what I have seen the lessons are being learnt. Last October, when a new British brigade took command in Helmand, its commander, Brigadier Andrew Mackay, declared “a concept of operations” where the death of enemy soldiers was no longer a measure of success. “The population is the prize,” Mackay wrote.

A campaign based on counter-insurgency principles, he said, needed operations designed not so much for “kinetic effect” (inflicting physical damage on the enemy) but calibrated to “influence” the population: decreasing support for the enemy and increasing the standing of the Afghan government.

I found morale among the troops high. There is a sense that a strategy for a victory of sorts is at last evolving. Now, rather than battling the Taliban head-on, they have decided their job must be to “hold the line” and createa space where development can happen. There is a recognition that killing the Taliban and smashing towns will not help in the longer struggle to stabilise Afghanistan; the only workable strategy is to convince the locals that the coalition is there to help.

This concept, that “the population is the prize”, had its greatest effect during last December’s operation to retake Musa Qala, which had been handed back to the Taliban a year earlier. The deployment of hundreds of British, American and Afghan troops around the town achieved such an “overmatch” of forces that, after initial fierce fighting, the Taliban were forced to flee – and the town was recaptured without being destroyed.

The key moment was the arrival of the military development experts, a so-called stabili-sation team. I watched as they unfolded precise blueprints for the construction of a mosque, for the rebuilding and reopening of a school and for roads and improvements to water and power.

Three months later, when I returned to Musa Qala, a small road had been built, the market was open, there was a new health clinic and a school teaching 800 pupils. On top of that a work scheme was employing 300 Afghans.

Ironically, it is in these very successes that the present danger to our troops lies. The more soldiers such as Gamble go out to talk to locals, or help them with development, the more vulnerable they make themselves to suicide bombers or roadside explosions as the Taliban – having been beaten in set-piece battles – switch to Iraqi insurgency-style tactics instead.

The main problem is that our troops can “hold the line”, creating a safe zone inside the front lines, but the government and other agencies are often not there to fulfil their part of the bargain. Despite the army’s good work in places such as Musa Qala, health and safety rules mean that Foreign Office officials find it hard to set foot outside their compounds and contractors are frequently unable to work. So at present there is a relatively safe space, created at high cost by British troops, where insufficient vital reconstruction is happening.

It takes immense nerve to take casualties yet still adopt a friendly pose to locals who could be the enemy. But if we are to stop Afghanistan once again being a lawless breeding ground for terrorists, there is no other way forward.

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