The remains, including bundles of bone in strips of military uniform, were found by officers from the 3rd Regiment of the Royal Horse Artillery in an abandoned Iraqi military base on the outskirts of Al Zubayr.

It was not known how long the remains had been there, but they will be investigated by forensic specialists as possible evidence of atrocities carried out by President Saddam Hussein's regime.

Al Zubayr is 20 kilometers (15 miles) southwest of Iraq's second city Basra, in an area secured by British troops allied with US forces which invaded the country on March 20.

Sky News, in a live report from west of Basra, carried video images of the morgue, showing a line of cardboard boxes with what appeared to be white shrouds in each of them.

A British soldier was also seen flipping through what appeared to be a handwritten list of the dead.

Captain Jack Kemp, 40, told the Press Association that he discovered "approximately 200 makeshift coffins" when he led a team of soldiers into the building for a security check.

"I wouldn't like to speculate, but the bones inside are obviously years old," he told the Press Association. "It is certainly not from the recent conflict but it could be from the one before."

He said the building had been declared off-limits to all personnel "and we will treat it as a mass grave."

In a graphic description of the scene, Press Association chief reporter Vanessa Allen, who is embedded with the British army's Royal Logistic Corps, told of cardboard coffins "stacked five deep in a warehouse."

A neighbouring building "contained apparent cells and catalogues of photographs of the dead, most of whom had died from gunshot wounds to the head."

"Others were mutilated beyond recognition, their faces burned and swollen in the faded black and white photographs," she reported. "Outside stood what one soldier described as 'a purpose-built shooting gallery'."

She said a tiled plinth, about a foot (30 centimeters) in height, stood in a courtyard, with the brickwork behind it riddled with bullets. Behind it was a drainage ditch.

"Inside the warehouse, one of the bags and coffins contained an identity card written in Arabic, while military webbing and boot soles were visible in others," she reported.

"Human skulls, their teeth broken and missing, looked out from other bags, bundled into the coffins."

SPACE.WIRE