Bentham’s Nuclear Bunker

On the moor between High Bentham and Clapham there used to be a secret military installation. Part of a national network whose purpose was to assist in the defence against nuclear attack, this is the story of Bentham’s Nuclear Bunker.

Following the First World War, the government concerned about the threat of attack by enemy aircraft, formed the Observer Corps. This new force was made up of local volunteers spread across the whole country. Their job was to recognise and identify hostile enemy aircraft flying overhead.

Observation posts were built on open and high ground. In more urban areas high buildings would be chosen, including one on the Brunswick Tower of Windsor Castle. These posts would usually be wooden or concrete platforms protected by sandbags. Each post would be manned by a minimum of three observers and would communicate to one of 39 control centres by telephone.

By the time of the Second World War, there were over 1500 observation posts, manned by more than 100,000 volunteer observers. Whilst the Chain Home radar system could track the approach of enemy aircraft, once over the coast it was these volunteer posts that played the vital role in monitoring aircraft movements. The Corps were bestowed with the Royal title by King George VI in 1941 in recognition of the important part they had played during the Battle of Britain.

A typical observation post c1939.

Following advances in aircraft and tracking technology, the need for visual identification of aircraft was much reduced. As the Cold War intensified the government decided to modify the role of the ROC to help with defence against Nuclear attack.

Between 1958 and 1968 the traditional observation posts were replaced by sub-surface reinforced concrete bunkers at a cost of around £5000 each. This created a network of 1563 bunkers built around eight miles from each other right across the UK. These were excavated to a depth of 25 feet. Inside was a large room containing detection apparatus, canvas chairs, desk and metal bunk beds. A smaller room with a chemical toilet cubicle was attached. Electric light was provided by a 12 Volt car battery, that could be charged from a small petrol generator. On the surface there were two ventilation ducts and a single hatch to access the bunker via a steel ladder.

Cross section of a typical bunker.

Each post would be manned by three observers, still local volunteers. Their task was to detect the size and direction of any nuclear blast and monitor the radioactive fallout. It was anticipated that the crew would need to remain underground for at least 21 days after an attack. The conditions could only be described as cramped, cold and damp.

The bunkers were grouped into clusters of between three and five, with one designated as a master. Bunkers communicated with the master using standard telephone lines, one of the best ways to identify one is a line of redundant telegraph poles that stop in the middle of a field. The master bunker was also equipped with radio communications in order to contact the regional control centre.

By 1968 the government had decided that the Cold War had begun to thaw, and the threat of nuclear war had eased. Many local areas were beginning to have trouble recruiting enough volunteers to man the bunkers in any case. The decision was taken to reduce the number of posts and the number was slashed by more than half. The remainder stayed in service until 1991 when the ROC was finally disbanded and all the observation posts closed.

A large number of the bunkers were filled in and demolished. Many of the sites were bought by mobile phone operators as their strategic locations on high ground were ideal for cellular radio masts.

Which brings us to the fate of the Bentham bunker. It was located on the side of the B6480 Clapham Road, just short of the Greystonegill Lane/Nutgill Lane crossroads. It closed in 1991 when the ROC was disbanded, and was finally demolished in 1997 when a mobile phone mast was built on the site.

Site of Bentham Bunker today.

Most of the neighbouring bunkers in the cluster have suffered a similar fate. Caton was located next to Bull Beck Picnic Site. It closed in 1968, and the bunker became a septic tank for the picnic site. The bunker at Settle was closed in 1991 and was located in a field between Anley Hall Nursing Home and Lords Close. It was demolished and nothing remains. At Horton-in-Ribblesdale the bunker was just north of St. Oswald’s Church. It closed in 1991 and has also been demolished.

However, the master station at Kirkby Lonsdale survives. It is located in a rectangular fenced compound next to the new Oakfield Park housing development adjacent to the QES Astroturf. Although it too closed in 1991, the surface features are still clearly visible. So next time you do the school run or go shopping at Booths in Kirkby, spare a thought for the brave volunteers of the ROC who manned the all the observation posts to help defend the country. The hatch is however firmly locked.

Kirkby Lonsdale Observation Post.