A cache of more than 180 Roman lead sling bullets - thought to be the largest ever found in Britain - has been unearthed in southern Scotland.

They were discovered during an archaeological dig at Burnswark in Dumfries and Galloway.

Investigations have been ongoing at the flat-topped hill near Lockerbie over the past fortnight.

Dark organic soil was also found nearby which could be the remains of a bag or sack for the bullets.

Archaeologists have been trying for centuries to assess the role of Burnswark in the Roman occupation

Some 1,800 years ago, Roman troops used "whistling" sling bullets as a "terror weapon" against their barbarian foes, according to archaeologists who found the cast lead bullets at a site in Scotland.

Weighing about 1 ounce (30 grams), each of the bullets had been drilled with a 0.2-inch (5 millimeters) hole that the researchers think was designed to give the soaring bullets a sharp buzzing or whistling noise in flight.

The bullets were found recently at Burnswark Hill in southwestern Scotland, where a massive Roman attack against native defenders in a hilltop fort took place in the second century A.D.