“Invasion is unlikely.” That’s what they said back in 1906 when the London Defence Scheme was officially abandoned but let me tell you about Fort Halstead. It’s a place that has reinvented itself many times. Fort Halstead sits high on the Kentish North Downs. It watches over Sevenoaks southeast of London.
Originally, Fort Halstead was built as part of London’s defenses. Construction occurred between 1895 and 1897. It was meant to protect the southern and eastern approaches to London. Imagine volunteers rushing here in a crisis. They would man the entrenchments against invaders. The fort would supply them with tools, stores, and ammunition.
But the threat of invasion decreased. The Royal Navy grew stronger. So the London Defence Scheme was abandoned. Many mobilization centers were quickly sold. Fort Halstead was retained. Perhaps it was kept to store equipment from other sites. During World War I, the London Defence Scheme was revived. Many entrenchments were dug. Fort Halstead returned to its intended role. A laboratory was built inside in 1915. It inspected ammunition.
In 1921, a retired colonel bought Fort Halstead. He lived in the laboratory. He rented out the cottages. The rest of the site became a campsite. Territorial Army soldiers, Boy Scouts, and Girl Guides stayed here. It even housed refugees.
Everything changed again in 1938. Fort Halstead became the home of the Projectile Development Establishment. Alwyn Crow led the team. They worked on solid-fueled rockets. This research had started at Royal Arsenal in Woolwich. The team primarily focused on anti-aircraft weapons. Over eighty new buildings were built around the fort. The work at Fort Halstead led to important weapons. The 7-inch Unrotated Projectile was used on Royal Navy ships. The 3-inch version was operated by the British Army. They defended the UK with Z Batteries. Other developments included the RP-3 anti-tank rocket. Also the Mattress and Land Mattress bombardment systems.
In 1940, Fort Halstead became a target. The Germans knew about the rocket development. The Projectile Development Establishment was evacuated to RAE Aberporth.
Later, the Design Department and the Research Department moved to Fort Halstead. It’s believed that Britain’s atomic bomb development began here. The project was hidden under the name “High Explosive Research”. William George Penney led the team. He was appointed Chief Superintendent Armament Research. The first atomic bomb was developed here. It was secretly transported to Australia for testing. It successfully exploded in the Montebello Islands. In 1950, the “HER” research moved to a new site. This was the Atomic Weapons Establishment in Aldermaston.
In 1955, the two departments merged. They formed the Armament Research and Development Establishment. It gained the title “Royal” in 1962. In the 1980s, RARDE merged with other establishments. These were the Military Vehicles and Engineering Establishment. Also the Propellants, Explosives and Rocket Motor Establishment.
After the Lockerbie bombing in 1988, forensic experts from RARDE examined the wreckage. They testified at the Pan Am Flight 103 bombing trial. In 1996, the Aldwych bus bombing remains were analyzed here. Previously, IRA explosive devices had been examined at Fort Halstead.
RARDE was home to military simulation and war game projects. They assessed future defense equipment. In 1990, computerised war games prepared for Operation Granby. This was Britain’s contribution to the Gulf War.
In 2017, scientists examined the wreckage of a Polish Air Force Tu-154 crash. They searched for traces of explosives. The Polish government engaged them.
Fort Halstead evolved into the Defence Evaluation and Research Agency in 1995. In 2001, DERA split into QinetiQ and Dstl. QinetiQ retained Fort Halstead. They leased part of it back to Dstl. The site focused on explosives research, testing, and forensic analysis.
In 2006, QinetiQ sold Fort Halstead to Armstrong Kent LLP. They remained on-site as tenants. In 2011, Dstl announced its facilities would close. Delays meant Dstl finally left in October 2022. In 2017, Armstrong Kent sold the site to Merseyside Pension Fund. Current plans include new homes and a business campus. QinetiQ will remain.
Fort Halstead has been a place of constant change. It has shifted from defense to research to development. It even contributed to atomic weapons. Now it’s evolving again. As you stand here consider the many layers of history beneath your feet.