The bloodiest day: blast kills six British soldiers as toll passes 400

Deaths in Afghanistan raise questions over safety of Warrior armoured vehicles

Six British soldiers are missing, believed killed, after a massive explosion in Afghanistan. The losses mark a new and violent milestone in the war amid indications that the attack was carried out by insurgents using a bomb of an unusually large size.

Click here to see the 'British troop deaths' graphics

The deaths were the largest number resulting from action in a single incident since British forces were deployed 11 years ago, and took the total number of fatalities to more than 400.

The men were on patrol in a hazardous area on the border between Helmand and Kandahar provinces when the Warrior armoured personnel carrier they were travelling in was blown up. The ferocity of the blast flipped the vehicle upside down and sheared off the gun turret, starting a fire which ignited ammunition stored inside.

The soldiers, five from the 3rd Battalion the Yorkshire Regiment and one from the 1st Battalion The Duke of Lancaster's Regiment, were just a week into their tour of duty. Troops in a second vehicle which was left relatively undamaged attempted to get to those inside the stricken Warrior, but were beaten back by flames and the risk of secondary explosions. Other forces which arrived soon after the initial reports of what had happened on Tuesday spent most of the night gathering remains and returning them to their base at Camp Bastion.

The commander of Task Force Helmand, Brigadier Patrick Sanders, said the Warrior involved in the blast suffered "catastrophic damage". The armoured personnel carriers, used extensively by forces on frontline duty in Afghanistan and Iraq, were due for a billion-pound upgrade, including equipment which would allow greater flexibility on attaching armour, announced by David Cameron last autumn.

The measure was taken after concern about the protection provided against IEDs (improvised explosive devices) was first raised in 2007 when four soldiers were killed in Iraq by a bomb which ripped apart the underside of their vehicle. At their inquest, David Masters, the coroner for Wiltshire, said he would be raising the issue with then Defence Secretary, Bob Ainsworth.

The Prime Minister said last October: "It's a £1bn investment – 90 per cent of the jobs and the work are going to be done here in the UK. That's good for the economy, it's good for our Armed Forces but only possible because we made difficult decisions."

A spokesman for the Ministry of Defence said last night: "The focus of the £1bn Warrior upgrade announced last year was to install a new 40mm cannon, add standard armour enhancements to allow for flexible detachable armour in the future and to extend the Warrior's life in service. Warrior has been upgraded throughout its service in Iraq and Afghanistan to tackle the threat from IEDs and mines. Warrior provides some of the highest levels of protection available but sadly no armoured vehicle can provide absolute protection from the very largest explosions."

The latest fatalities raise the number of UK military personnel killed in Afghanistan to 404. Until now, the highest number killed in one attack was in July 2009, when five British soldiers died in an IED blast in Sangin, and November of the same year, when five more were shot dead by an Afghan policeman they were training at base Blue 25 in the Nad-e-Ali district of Helmand province. A total of 14 servicemen died in an accident when their Nimrod aircraft crashed in 2004.

Mr Cameron said yesterday: "This is a desperately sad day for our country and desperately sad of course for the families concerned. It is a reminder of the huge price that we are paying for the work we are doing in Afghanistan and the sacrifice that our troops have made and continue to make."

Ed Miliband, the Labour leader, said: "This is a dark day. We salute all of our fallen and those who continue to serve in the face of the gravest danger."

General Sir David Richards, the Chief of the Defence Staff, said he was "deeply saddened" by the news.

"The courage, fortitude and determination of those servicemen and women currently in Helmand is inspirational," he said. The Archbishop of York, John Sentamu, said his heart went out to those affected.

Helmand attack area was meant to be safe

The blast that killed the British servicemen occurred in an area which the Taliban consider their heartland but which was supposedly "cleared" of insurgents in a series of operations by US, British and Afghan forces. The attack shows the ease with which Afghan fighters are able to return and place improvised explosive devices (IEDs) at relatively little risk to themselves but with lethal impact.

Western and Afghan officials insist that large numbers of bombs have been recovered after tip-offs from locals. But although the Talibs had previously been driven away from the border area between Helmand and Kandahar, they have repeatedly returned and been able to set up bases, either because residents of the sparsely-populated hamlets are intimidated, or because they actually support the Taliban.

Local people are aware that Nato troops will be leaving soon, and there is uncertainty about the ability of Afghan security forces to protect them from the insurgents in the aftermath. There is also confusion caused by statements from the government of Hamid Karzai and Western states about negotiating with the Taliban, and what degree of power the Islamists will hold in the future.

Kim Sengupta