A Cold War bunker that has been buried for decades has been discovered during an archaeological dig at Scarborough Castle. English Heritage unearthed the forgotten lookout post last weekend, which would have been used by the Royal Observer Corps to track the threat of nuclear bombs.

Constructed between 1963-64, it was one of more than 1,500 posts used across the UK during the Cold War, used to detect nuclear explosions during a time when the threat of nuclear warfare loomed. Designed to withstand attack, the posts were built to a near identical specification, with communications facilities and bunk beds for members of the ROC, a civil defence organisation largely made up of volunteers, created to detect, identify and track aircraft over Britain.

Ever since it was sealed and buried in 1968, its location and condition have remained hidden within the headland on the grounds of Scarborough Castle.

But last weekend, experts at English Heritage, supported by the National Lottery Heritage Fund, discovered the entrance after beginning the archaeological dig on March 7. They had identified its location through data analysis and a ground survey.

Images show some of the brickwork fully intact, including one bearing the wording 'Scarborough' chipped into the block. The entrance exterior appears to be made of brick, encircling a possible concrete or stone centre, where exposed metal spokes are visible.

Kevin Booth, head of collections at English Heritage, explained why this location was particularly strategic for the ROC.

He said: “Wherever you lived in Britain you were probably no more than a few miles from an ROC post – yet few people knew they existed.

"It seems strange to have a Cold War bunker built inside Scarborough Castle, but in many ways it is a perfect location: this headland has been an observation post for thousands of years, from bronze age settlement, roman signal station, medieval castle, WWI gun battery and, here, a 1960s concrete bunker watching for armageddon”.

It bolsters the charity’s continued efforts to tell the story of this unsung ROC organisation, which had more than 20,000 volunteers.

Founded in 1925, the group played a crucial role in World War II and it was given Royal status following its contribution to the Battle of Britain.

Helen Featherstone, director of North England at The National Lottery Heritage Fund, said "It's really exciting that this lost bunker has been uncovered by the team working on this project marking 100 years of the Royal Observer Corps.

"This find builds on our understanding of their story and shines a spotlight on their important work protecting the UK."