Digger driver Stephen Dunn got the shock of his life after unearthing 15 anti-tank shells on land believed to have been used as a former Second World War munitions dump.

The 25-year-old yelled to his workmates to get clear after spotting the unfired shells in the bucket of his JCB yesterday morning.

Police sealed off the immediate area in Thornaby, Teesside, shortly after Mr Dunn dug up the shells at 8.50am.

They later decided to close the nearby A66 in both directions from the Yarm Road turn-off to the Thornaby turn-off between 10.10am and 10.45am as a precaution - causing major disruption to motorists. Part of Thornaby Road was also closed.

The Royal Logistical Corps Bomb Disposal Army Unit from Catterick in North Yorkshire were called to the site next to The Royal George in Sun Street. They found the shells contained no explosive.

The shells are mainly eight pounders up to 3ft in length. All date from the Second World War.

Police have been told the site, which once adjoined the now closed Thornaby Aerodrome, was previously used as an army and navy munitions dump.

Mark Dowdall of developers HJ Banks, explained that Mr Dunn and his workmates had been digging up 3metre-deep loose earth to prepare the site for the building of houses and flats.

He said Mr Dunn scooped up the shells in only his second dig of the day.

"Stephen did the right thing getting everybody safe. However the Royal Logistics bomb squad soon established there were no explosives in the shells," he added.

"They appear to be dummies and are filled with concrete and steel. We are excavating the entire site and are working closely with the bomb squad to make sure the whole area is totally safe."

A police spokesman said the alert had caused heavy tailbacks of traffic, which soon cleared once the roads were reopened.