Troops have also been also resorting to ripping out internal ceramic plates from the armour to give themselves better freedom of movement under fire, the newspaper said. Described by Defence Secretary Des Browne earlier this year as "a world-leading system", Osprey Improved Combat Body Armour was designed to give better protection for forces facing attack by insurgents.

The equipment given to soldiers on normal operation duties includes thicker ceramic plates inside the armoured vest.

Because of their more vulnerable position, top gunners on vehicles have been kitted out with an enhanced version called Kestrel, which also includes neck and arm protection.

The newspaper quoted one unnamed marine as saying: "It's hard to run for cover wearing Osprey. They're heavy, but more importantly they're so bulky you can't even bend down. Worst of all, you can't fit your weapon to your shoulder."

But the MoD insisted that the new protection had been rigorously tested. A spokesman said: "Osprey body armour was widely tested by soldiers in the Infantry Trials and Development Unit (in Warminster, Wilts). It offers superb protection."

He added: "Any issues with equipment should be reported through the chain of command."

The death of Sergeant Steven Roberts during a riot in Basra in March 2003 sparked a storm after it emerged that he had been forced to give up his enhanced body armour before going into battle.

Defence personnel being sent to Iraq or Afghanistan are now not allowed to travel without enhanced combat body armour.

Body armor carriers