Barrage Balloon Mooring Site, East Of 57 Oak Tree Avenue

This is a World War II barrage balloon mooring site, dating from approximately 1938-40. The site consists of pre-cast concrete blocks, each with a cast-iron ring set into its upper surface, arranged in a circular pattern and set flush with the ground. Outside the central anchorage, a second circle of mooring blocks, approximately 11 metres in diameter, marks where guy ropes would have been fixed when the balloon was fully positioned. Beyond this is a shallow circular ditch approximately 27 metres in diameter, which would have accommodated the trailer winch used to wind the tethering ropes up and down.

Historical Context

Hydrogen-filled barrage balloons were developed as anti-aircraft devices towards the end of World War I to protect London from low-level air attack. Following successful trials with groups of three balloons suspended above the city—the first operational by October 1917—the scheme was abandoned after the war. Renewed experiments at the Royal Airships Works at Cardington in Bedfordshire during 1926-8 proved so successful that Air Vice-Marshal Sir Edward Ellington, Commander-in-Chief of Air Defence of Great Britain, recommended a balloon barrage as part of London's air defence, maintained in readiness. The Air Ministry approved the establishment of a low-altitude barrage balloon section in 1932, formed in 1935 at RAF Cardington under RAF Fighter Command. As the threat of war became apparent, Balloon Command was established on 1 November 1938 as a separate entity. Training units at Cardington and Larkhill trained approximately 5,000 RAF balloon operators, 5,000 WAAFs, and around 12,000 operators and drivers before their closure in November 1943.

Eighteen balloon depots were established across the country between 1938 and 1940, each servicing one to four balloon squadrons positioned to defend vulnerable targets including naval bases, major cities, ports and industrial plants. By 1939, balloons were tethered by a single cable containing cutting links, with parachute packs attached above and below. When an aircraft struck the cable, it would be severed, leaving the aeroplane trailing two parachutes to increase drag and cause a crash. A ripcord on the cable would simultaneously open a patch on the balloon to ensure its descent and recovery.

Pucklechurch was built around 1938 as No.11 Balloon Centre, defending the city of Bristol, the aeronautical manufacturing works at Filton, and the strategic docks at Avonmouth. Damaged barrage balloons from combat or accidents were brought to the site for repair. The centre comprised four balloon workshops, of which two survive largely unaltered and were listed at Grade II in 2003. The mooring site lies approximately 390 metres south-east of these listed workshops. RAF Balloon Command was disbanded in January 1945; Pucklechurch subsequently became RAF Pucklechurch, passing to its parent unit at RAF Filton and later the Maintenance Unit at Quedgeley. The station served in troop demobilisation and as a balloon storage facility through the 1940s and 1950s before closure at the end of 1959. The western part of the site was transferred to HM Prison Service in 1962 for the construction of Pucklechurch Remand Centre (now HMP and YOI Ashfield), while the remainder became a trading estate. The balloon mooring site now sits in a green space within post-war housing development.