While building a new service area for lorries at the Lao-Vietnam border, the driver of an excavator thought he had hit a tree stump and adjusted the angle of his digger to remove the obstruction.

On hearing a distinctive ‘clang’ over the growl of the engine he paused, clambered out of his cab and went to investigate. On seeing the source of the clang, he ran for help.

Delays are not welcome here. Trade across the border at the once sleepy village of Langkhan, in Khammouane province, central Laos, has increased enormously over the past five years and a larger parking area for trucks waiting to cross the border is badly needed.

This time, however, delay was inevitable. The driver had uncovered another reminder of the Indochina war that raged all around this site nearly 50 years ago. In this case it was an American 750lb MK117 bomb, complete with deep score marks were his digger’s bucket had just missed the nose fuse.

Langkhan was once on the central part of the Ho Chi Minh Trail, a route through Laos and Cambodia that allowed the North Vietnamese to supply forces in the south fighting the US-backed South Vietnamese government.

From 1964 to 1973, the United States air force and navy dropped more than two million tons of air-delivered munitions on Laos, including more than 270 million cluster bombs, a rate of one planeload of bombs every eight minutes. This amounted to more than all the air-delivered munitions dropped on Germany and Japan in the Second World War.

An estimated one third of these bombs failed to function, leaving a legacy that remains to this day.

On hand to deal with this latest find was a team from the Mines Advisory Group (MAG), a British NGO operating in Laos since 1994. The bomb was made safe and moved to a demolition site for destruction.

Thanks to recent British funding – £10.5 million over three years for MAG and two other operators in Laos – the organization has expanded its operations in Khammouane province, increasing its presence from six clearance teams to 16.

Each team has 13 members, recruited and trained from the local population. In addition, MAG has technical survey and community liaison teams to ensure the clearance occurs where it is most needed.

Explosive contamination affects all aspects of life in this remote region. Swaths of land are left uncultivated as they are too dangerous to work. Most explosive injuries and deaths occur to people working on the land.

In addition, every time a road is built, a power line extended, the foundations of a school laid down or a well or bore hole dug, the land has to be searched and made safe. This all adds to the cost of development projects and causes delay creating a sense that development is creeping along, rather than making the great leaps forward that have been accomplished in other parts of the region.

Cluster munitions were intended to penetrate the dense jungle canopy and disrupt vehicle convoys and troops who were using the Ho Chi Minh Trail to supply the main North Vietnamese Army and Viet Cong guerrillas in South Vietnam. Because of this, much of the land through which it passed remains covered in scrub and undergrowth, including what was farmland before the war.

The significant British government support means that systematic clearance can now take place all the way to Boualapha, the district capital of Boualapha district, the point where MAG’s areas end and our colleagues from UXO Lao, a largely American-funded outfit, take over the challenge.

This work has enabled farmers to extend land under cultivation. Kayou village used to have nine contaminated rice fields but now has 60 fields that have been cleared and are safe to use. With a new irrigation system, the village gets two crops a year.

With a promised road upgrade, this previously neglected corner of Laos can begin to prosper. With scenery to rival and arguably surpass neighbouring Thailand, and with safe trekking and rock climbing, people in Khammouane province hope to lure some of their neighbour’s millions of visitors over the border.

In a region dominated by China, the right aid, that brings benefits long into the future, will be a factor in ensuring that Britain is known as a generous and consistent partner and an international force for good.