British troops combat the use of IEDs in Afghanistan

A photograph taken from a Tornado GR4 fast jet

This image from a Tornado GR4 fast jet shows an area of suspected insurgent activity with Warrior armoured vehicles of the 1st Battalion Scots Guards in the distance

Improvised Explosive Devices (IEDs) have been the biggest single killer of troops in Afghanistan.

But the Ministry of Defence (MoD) has said British troops in Helmand province, southern Afghanistan, are stepping up their efforts to stop insurgents laying roadside bombs.

The use of IEDs was a highly successful tactic for insurgents in Iraq.

Their strength as a weapon lies in the fact that they punish the need for coalition forces to use slow-moving convoys of heavy vehicles to replenish smaller units fighting in the mountains and deserts.

THE IED THREAT

1. ROADSIDE IED: Hidden insurgent detonates device by wire

2. REMOTE DETONATION: Bombs can also be set off by radio or mobile phone signal

3. LANDMINE: Buried below the road surface, detonated by pressure of passing vehicle

The device itself consists of an adapted landmine or artillery shell rigged up to a makeshift detonator.

The bombs are often placed on a roadside and can be detonated by wire by a hidden insurgent when military vehicles pass.

More sophisticated IEDs are rigged up to tripwires which act as booby traps, or are detonated via radio or mobile phone signals.

The extent of the damage caused by an IED depends on the quality of explosives and materials available, and the skill of the bombmaker.

A British military spokesman said there had been numerous strikes on insurgents and a number of arrests in recent weeks.

The BBC's Jonathan Beale reported that in one such incident, on 18 March, the MoD said combined Afghan and ISAF forces had detained three men suspected of manufacturing roadside bombs.

An AK 47 weapon and 60 kilos of opium were also recovered in the search.

Sangin, in Helmand province, remains the most challenging area for British troops in Helmand.

Meanwhile, the MoD has released photographs taken from a Tornado GR4 fast jet earlier this month in support of Operation Moshtarak - the offensive taking place in central Helmand.

The grainy black and white images show what is described as an IED team trying to lay bombs close to British troops operating in the semi-desert area north of Nad e Ali.

The first photo shows the area with Warrior armoured vehicles of the 1st Battalion Scots Guards in the distance.

Four people were reportedly digging in the desert to lay bombs here

The Scots Guards had called in the Tornado's to help search for IED activity.

The second photo is a close up of the area in which four individuals were reportedly digging in the desert to lay the bombs.

A live feed from the Tornados was relayed to the battalions operations room where the forward air controller was able to monitor the activity in real time.

He then ordered the Tornados to continue their surveillance while an armoured ifantry platoon tried to intercept the suspects.

The third photo shows the Warrior tanks closing in on the area. In this case there was no request for the Tornados to fire their weapons as there was no immediate threat to life.

Warrior tanks are shown closing in on an area where IEDs were to be laid

Ground forces moved into a compound seen in the distance where they detained a suspected insurgent.

The platoon then carried out a detailed search of the area using EOD or bomb disposal teams.

In his report of the incident on the 10 March, the forward air controller said the "speed of reaction and close co-ordination of everyone involved in the operation has sent a clear message that ISAF forces can appear anywhere, at any time".