In June 1940 General Sir Edmund Ironside, the Commander-in-Chief of Home Forces drew up emergency plans to build static defences to interrupt and delay progress of any invading forces. The strategy was to strengthen the coastal defences or the ‘Coastal Crust’, as the first line of defence.
The Coastal Crust consisted of defence batteries, pillboxes, barbed wire, scaffolding, mined beaches and anti-tank obstacles.
Defensive static ‘stop-lines’ were also built to impede the progress of an invading force.
The construction of defence lines was intended to delay enemy progress sufficiently long enough to allow mobile defending forces to reach the invasion points and counter attack.
The General Headquarters Lines (GHQ), were linear defence lines designed to provide protection to London and important industrial manufacturing areas in the Midlands and the North. These main defence lines were supplemented by further stop-lines.
The Eastern GHQ stop-line was designed to run from north of Edinburgh, inland and south along the east coast, around the east of London to meet the south coast near Eastbourne.
Two further lines ran east to west to impede forces progress northwards. These were known as Stop-line Red and Stop-line Blue.
Stop-line Red followed the Thames from Reading and crossed the Cotswolds to Great Somerford in Wiltshire, and Stop-line Blue followed the Kennet and Avon Canal to Semington.
These lines met Stop-line Green, which encircled Bristol.
Stop-lines were designed to take advantage of natural terrain wherever possible and this principle was applied to Stop-line Green. It was agreed that the route would run from the Severn, south of Bristol, to again meet the Severn near Upper Framilode in Gloucestershire.
The pillboxes along the nearby Stroudwater Canal and River Frome formed part of Stop-line Green.
Stop-line Green, was often referred to as “The Bristol Outer Defence Line”, and its purpose was to protect the industry of Bristol and the port of Avonmouth from an inland attack from the east.
The protected area would also have included the Severn railway tunnel and the Severn railway bridge.
The stop-line ran for approximately 90 miles and included 18 miles of dug anti-tank ditch, around 370 pillboxes planned/built and over 250 road blocks.
This particular part of Gloucestershire was considered important, with many features that would have been very beneficial to an invading army. These included the River Severn as a navigable route up to Tewkesbury also the shallow beach or mudflats could have afforded easy landing access to an invading force. The Gloucester and Sharpness Canal could also serve as a vital supply route.
Therefore, the Severn Estuary was defended with heavy AA positions situated at various points and a number of pillboxes along the eastern bank of the estuary forming part of the Coastal Crust from a point south of the end of Stop-line Green at Upper Framilode.
A number of pillboxes remain along the Dumbles at Slimbridge and if you look towards the river from this cache you will see one of them.
Thanks to the Gloucestershire Society for Industrial Archaeology and Alan Strickland for the history and inspiration for this cache.
The cache is a clipbox in a camo bag, ideal for small swops and geocoins.
Happy Hunting ...........