Roadside bombs: 'The deadliest weapon' in Afghan war
The roadside bomb killed thousands in Afghanistan last year, stifled the economy and created a climate of fear - yet its capacity to wreak destruction and havoc only seems to be increasing.
The exact toll is difficult to calculate but the interior ministry says the majority of 1,800 Afghan national police killed last year, died as a result of roadside bombs.
In addition, about 900 Afghan National Army soldiers were killed by roadside bombs - averaging three soldiers a day, according to General Zahir Azimi, spokesman for the defence ministry.
Over the last two years, the insurgents' focus on roadside bombs - also known as improvised explosive devices (IEDs) - has gained momentum.
They no longer want to take on Afghan and Nato forces face-to-face, says Haji Abdul Mutalib, district governor of Marjah in Helmand province.
Instead, they are packing TNT and plastic explosives - as well as metal and ball bearings - into their bombs to make them more powerful and more destructive, he says.
Due to increased investment by al-Qaeda, a growing number of Afghan insurgents now have the expertise to make such bombs.
But they are also outsourcing the job of bomb-making and planting the devices to young jobless men, according to intelligence sources in the south. And every target has a price - whether a police officer or a district governor.
The growth in bomb use has also had the unlikely impact of straining relations with Pakistan.
The Afghan government complains the fertiliser used in bomb-making comes from Pakistani factories.
The structure of the bombs is basic but very effective, and difficult to detect.
Last month in Kandahar province, more than 1,000 roadside bombs were found in the Panjwai district. And, according to the regional police chief Abdul Raziq, there are thousands more.
Almost daily, Afghan forces are focused on finding and defusing these bombs. It is not unusual for them to be tipped off by farmers, shopkeepers, butchers or villagers who might find one under a bridge or in a field.
By laying bombs where ordinary people live and work, insurgents have ensured roadside bombs remain the biggest killer of civilians in Afghanistan.
Over the last year, entire families travelling together in a van, perhaps to a wedding, funeral or picnic, have been blown up, leaving 15 or so men, women and children dead.
The devices, often detonated through mobile phones or timers, may be powerful but they are not accurate.
The tactical advantages of roadside bombs are many.
They allow insurgents to block the country's main arteries, cutting off areas and causing serious food and medicine shortages.
One road, on the borders of the remote provinces of Daykundi and Uruzgan, usually used by thousands of people, has been closed for five weeks.
Insurgents have lined it with bombs to stop people travelling and supplies being delivered.
In other instances, construction projects have been cancelled.
And, in rural Afghanistan, these bombs have stopped children attending school, and at worst, killed some.
They are also laid on routes that insurgents know will be used by Afghan forces about to carry out operations or make arrests.
Stopping the spread of these bombs is proving hard. Without helicopters, the local and national police are the most vulnerable.
The Nato-led International Security Assistance Force (Isaf) use drones to detect insurgents, and security cameras on blimps are an aid, but the Afghan government does not have the same capability.
However, together with Nato, the government is targeting the Taliban commanders responsible - a side of the story that often goes unreported.
Earlier on Wednesday, in the same district in Helmand where three British soldiers were killed on Tuesday, a roadside bomb killed the head of the High Peace Council for Helmand Province, Raees Malim Shah, and two policemen.
They had gone to carry out an assessment of the security situation. Now, it means Afghan officials will no longer be able to go to that area.
The roadside bomb has, without doubt, been one of the deadliest weapons in this war, and it remains so.