A 2,000-year-old mass war grave crammed with up to 50 headless bodies has been uncovered by workers building a road for the 2012 Olympics.

The Iron Age victims are thought to have been slaughtered by the invading Romans in about 43AD.

The ancient burial pit was discovered on Ridgeway Hill near Weymouth, Dorset, close to Maiden Castle, Europe's largest Iron Age hill fort.

The site is being dug to make way for the so-called Olympic Highway, an £87m relief road for the 2012 Olympics.

Dave Score, project manager for Oxford Archaeology, which is managing the dig, said it was a "remarkable and exciting" discovery.

He said: "We have counted 45 skulls so far, these are in one section of the pit, and several torsos and leg bones in separate sections of the pit."

Archaeologists are waiting to carry out radio-carbon testing on the remains but believe the skeletons were local men, killed by Roman soldiers.

The burial pit is around six metres in diameter.