Scarborough’s Royal Observer Corps Monitoring Post
The headland where Scarborough Castle is situated has stood watch over the Yorkshire coastline for over 300 years. In 1963 the global political tensions of the Cold War required a new lookout to be constructed within the castle walls. Buried beneath the outer ward is a tiny concrete bunker designed to protect three people in the event of nuclear war. The bunker, known as a monitoring post, was staffed by volunteer members of the Royal Observer Corps (ROC).
The Scarborough Monitoring Post was one of over 1500 constructed by UKWMO, the United Kingdom Warning and Monitoring Organisation. The posts were designed to give basic shelter to ROC personnel whose role was to record data on nuclear explosions.
At Scarborough, as with all posts, there was equipment to help plot the ground zero of a bomb, its altitude, its power and subsequent radiation passing across the headland and town. With its coastal location, the Scarborough post could plot bombs exploding over the sea, part of Soviet plans for war that could cause tidal surges devastating coastal areas.
Anatomy of a Monitoring Post
Most monitoring posts were constructed by local contractors working to the same basic design. A hole up to 4.5m deep was excavated, then shuttering was constructed and concrete poured to form the main chamber, which was around 6m long. The chamber was then buried in earth. An access shaft with metal ladder rose from one corner to above ground level, closed by a heavy hinged metal hatch. At the far end of the chamber a second shaft ensured ventilation of the space below.
Fred Tyreman worked for a contractor in Whitby and constructed some of the local posts, doing work from the shuttering and pouring of concrete to finally installing desks and cupboards. He recalled whitewashing the internal walls with ‘three coats with a six-inch brush – you needed sunglasses in there by the time we had finished!’
Royal Observer Corps volunteer Tony Metcalf remembered, ‘There was no heating at the posts, it was just a concrete shed that you're sat in, and after five or six hours. It got pretty cold in there.’
Equipment for spotting and measuring bombs was installed above the ground. Inside the bunker walls there were instruments and charts. Calculations were made on a long table, and a telephone provided a critical connection to the world outside. Bunkbeds were provided to allow two of the three observers to rest at any one time, and a portable toilet was discreetly accommodated behind a screen at the base of the shaft.
A short-lived post
The post at Scarborough was one of the last to be constructed as the UKWMO network neared completion. Just five years later the post was closed as part of a restructuring of UKWMO and a reduction in post numbers to around 800.
All evidence of the bunker above ground was demolished and the area returned to rough grass, indistinguishable from the rest of the headland. In the decades since closure the location, and even the existence, of the post was largely forgotten.
Finding the Post
As part of a 2025–6 project to commemorate the 100th anniversary of the formation of the ROC, English Heritage undertook an investigation of the post at Scarborough Castle. Using contemporary photographs, modern survey techniques and personal memory it was possible to establish the approximate location. Specialist geophysical survey then helped pinpoint the solid concrete shape looming beneath the turf line.
The castle is a scheduled ancient monument, so permission to excavate had to be granted by the Government. With this in place the hunt for the lost post could begin.
Found, Flooded but Fabulous
Over four days in March 2026 archaeologists revealed the remains of the post, recording its construction and condition. ROC members call the Scarborough-type a ‘Brick and works’ post, meaning the shape of the structure was built in brick first before concrete was poured. Several of the bricks excavated were stamped ‘Scarborough’ and had been manufactured at Seamer Road on the edge of town.
The main access shaft was capped in concrete, which the team removed. We discovered that the whole bunker was flooded almost to ceiling level and could not be pumped dry within our time on site. However, the waterlogged environment had helped preserve some of the bunker’s surviving features: the wooden door into the chamber was closed, solid to tap, and retained a clean coat of paint!
The team then excavated the broken-off ventilation shaft at the far end of the post, which was emptied of debris so a flexible CCTV camera could be passed into the void of the chamber. The image confirmed the level of flooding but also gives tantalising clues as to the survival of internal fixtures and fittings.
It was impossible to fully reopen the post, but bringing its story back into the public mind after 58 years buried has renewed the sense of the site’s long history and modern relevance.
Acknowledgement
English Heritage would like to thank members of the Scarborough Archaeological Society for their support, good humour and commitment to this project.
Find Out More
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Scarborough Castle
Visit Scarborough Castle to enjoy amazing coastal views, 3,000 years of history and a huge site to explore.
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Commemorating 100 years
Discover the project Forewarned is Forearmed, supported by the National Lottery Heritage Fund, and delivered in partnership with Digital Drama.
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History of the ROC
Read about how thousands of Royal Observer Corps volunteers gave up their time to protect their fellow civilians over a period of 70 years.
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The Cold War
After the Iron Curtain divided the world, Britain became an atomic power and fought in proxy wars. Learn about the threats and tensions of the Cold War era.