The Cold War Warrior is no match for a Taliban bomb in the ground

The Warrior armoured vehicle in which six soldiers lost their lives has been repeatedly criticised for the poor standard of its armour.

Coroners have condemned the Armed Forces for fielding the Cold War era vehicle because its flat bottom will always be vulnerable to bombs planted in the ground.

Since the 2003 Iraq invasion, a dozen Warriors have been destroyed with the loss of 28 lives.

The latest deaths will add to growing concern about whether the British Army's tanks and vehicles have enough protection.

While the Ministry of Defence has taken belated steps to address the problems, the Taliban have often been one step ahead with their techniques and tactics.

Dozens of soldiers have died in vehicles such as the notoriously weak Snatch Land Rover, now withdrawn from operations, and the Viking, Wimik and Vector vehicles.

The last government came in for heavy criticism for failing to withdraw Snatch after 37 deaths in Iraq and Afghanistan.

Commanders claim that if bombs are big enough, deaths cannot be prevented, but there have been no fatalities in the mine-resistant Mastiff vehicles that have been operating on the front line since 2006.

Following an inquest into the deaths of four British soldiers killed in a Warrior outside Basra, Iraq, in 2007, the coroner, David Masters, said he would "urgently seek" what could be done to improve its protection.

The MoD upgraded 70 Warriors at a cost of pounds 570,000 each, putting more armour on the underbelly and improved seating, although because of space and design issues they were unable to fit "blast attenuation" seats in the rear. Ministers are expected to ask urgent questions over whether the remaining dozen Warriors in Helmand should be withdrawn from operations.

While they provide off-road capability and firepower that mine-resistant vehicles such as Mastiff do not, Warriors are not designed for counter-insurgency warfare.

By comparison, the Americans have pulled out their Bradley armoured personnel carriers, their equivalent to the Warrior, and almost exclusively use mine-resistant vehicles.

Taliban bomb-planting has become so advanced that standard British mine detectors struggle to find devices with very low metal content.

The general issue Vallon metal detector was condemned by a coroner as "as anything but foolproof as it turned out not to be, tragically" after it failed to detect three bombs, one of which killed Craftsman Andrew Found in the Gereshk Valley last June.

The Scarborough coroner Michael Oakley said the 27-year-old's death underlined that Taliban fighters had progressed from "rudimentary to sophisticated" warfare. The Government has been accused of an "unforgivable breach of trust" for a shortage of weapons, protection and helicopters during the early years of the campaign.

Taliban bombing has forced the MoD to withdraw several poorly designed or protected vehicles including the Vector, Wimik and Viking.

Airmen have also been let down by poor standards after the death of 14 servicemen when an RAF Nimrod surveillance aircraft came down over Kandahar in 2006. It was found that a faulty fuel pipe caused the accident that led to the grounding of the entire fleet.

An MoD spokesman said: "Through state of the art equipment, every effort is made to minimise risk on operations but it can never be removed entirely."