William commander killed by Taliban bomb after delayed convoy was left without support

Major Alexis Roberts, 32, died instantly when his armoured vehicle was hit by an Improvised Explosive Device (IED) in Helmand Province last October.

The married father-of-two, known to friends in the Gurkha Rifles as "Lex", had been responsible for training Prince William as his platoon commander at Sandhurst.

Major Alexis Roberts (left) died instantly - Prince William was 'deeply saddened' by his death

An inquest heard Major Roberts was in charge of a 30-vehicle convoy negotiating a stretch of road nicknamed "IED alley" when the fatal blast occurred 19 miles from safety.

He was travelling in a Vector armoured vehicle which has been widely criticised for failing to provide enough protection against roadside bombs.

The convoy was due to reach its destination under the cover of darkness but a series of breakdowns, communication, and navigational problems delayed it by several hours.

As a result its air support unit ran low on fuel and had to return to base before daybreak - leaving Taliban forces clear to lay their trap.

Coroner David Masters told the inquest in Trowbridge, Wilts., that there were "three main delays" which would have concerned Major Roberts.

One was a hold-up caused by a vehicle which left the road, one vehicle broke down and had to be towed, and there was one navigational error.

Mr Masters said: "There was known to be an ever present threat from improvised explosive devices with perhaps a lesser risk of ambush, small arms fire and rocket propelled grenades.

"As the convoy entered a built-up area nothing stood out as suspicious. The top cover's concentration was on a group of people when there was a massive explosion.

"The vehicle in which Major Roberts and the others were being conveyed was thrown up into the air and went forward some distance before falling to the ground.

"Major Roberts took the full force of the explosion and must have died instantly. There was a large crater left in the road and he had sustained catastrophic injuries.

"At the time of the explosion they had no air support." 

Major Roberts, of 1st Battalion The Royal Gurkha Rifles, was killed on October 4 2007 during Operation Palk Wahel to flush out militants in Helmand Province.

He was leading a 30-vehicle convoy from Camp Bastion to Kandahar Airfield when his Vector vehicle was hit by an IED at around 8am.

The Pinzgauer Vector was one of 100 sent to Afghanistan last year to replace the ageing fleet of Snatch armoured Land Rovers, but which have failed to adequately protect troops.

The group hoped to reach safety before first light at 5am but the delays left them without air cover from 4.30am onwards.

Air support is crucial to spot potential dangers on the road ahead and to deter militants from laying roadside bombs as vehicles approach.

Furthermore, a breakdown in vehicle-to-vehicle communication caused the convoy to split into two separate parties 5km apart.

This was caused by Electronic Counter Measures (ECM) - which are used to detect laser operated and radio-controlled roadside devices - blocking radio signals between vehicles.

Major Douglas Reid, a passenger in the Vector vehicle with Major Roberts and from the same Battalion, said the road they travelled along is known as "IED alley." 

He said: "Major Roberts had mentioned that there was an area on the route called IED alley but he hadn't talked about any specific spots just a general threat.

"We were moving along and there was a massive bang the vehicle was thrown up and turned through 90 degrees. Obviously the vehicle landed and at that point it became apparent we had been hit.

"I looked forward and there was just a big space where Major Roberts should have been sitting - he wasn't there." 

The home-made bomb comprised explosives packed tightly into a cooking pot and was triggered by Taliban militants using a 300metre "command wire".

Major Roberts died instantly in the blast, which left a 4 1/2ft deep crater, and two other seriously injured soldiers had to be airlifted to a field hospital at Camp Bastion.

Major Roberts, who served as an instructor at the Royal Military Academy of Sandhurst for nearly two years, lived in Deal, Kent.

He is survived by his wife Susie - who attended yesterday's inquest - and their two young daughters Alice and Freya.

Prince William was said to be "deeply saddened" by the death of his "good friend" and attended his funeral at Canterbury Cathedral.

The inquest continues.