Site of Second World War floodlight, West of Lyons Hall, Great Leighs (EHER 20997)

Now destroyed. The site of a Second World War floodlight and generator building which can be seen in an aerial photograph from October 1946. The floodlight was probably constructed between 1936 and 1940 as part of an experiment to light up the night sky with a grid of large, fixed 'floodlights', as a defence against German bombers. The experiment, termed 'Silhouette', failed as the network of floodlights acted as a navigational aid for the enemy aircraft, and it was subsequently terminated in March 1940. When visited in 2006, nothing of the floodlight or the generator building remained.

February 2006. World War Two Defences in Chelmsford survey: site visit and desktop research. An aerial photograph taken in October 1946 shows an experimental 'floodlight' standing in a meadow to the west of Lyons Hall, south of Goodmans Lane. Although nothing remained of the central mirrors at that time the twelve sides can be easily seen. A few yards away to the north-west, the base of the generator building still remained. <1> Nothing of it now survives. <2> During the late 1930s/early 1940s (probably 1936-1940), an experiment was conducted to light up the night sky with a grid of large, fixed 'floodlights', as a defence against German bombers. Each installation consisted of a steel enclosure, 50 feet across, in which the floodlight was mounted, surrounded by twelve large mirrors angled towards the sky. Information on the experiment is still scarce; an enquiry to the Imperial War Museum has been unsuccessful. Enquiries by Mr F. Plume at the Public Record Office (PRO) in 1992/1993 have resolved some of the questions. <3> <4> A map drawn by Mr Plume in 1999, from his earlier investigations, shows 50 sites in Essex, located in an area from Little Leighs in the North to Eastwick in the South. It is not known whether this was the complete grid (although one floodlight is known to have been sited at Dovercourt, EHER 10715) or whether the experiment overlapped to other counties. The experiment was not a success - it is said that the light reflecting from the clouds lit up the countryside as a perfect navigational aid for the bombers, and the work was terminated in March 1940. <5> <6> The project was termed 'Silhouette'. <7> See EHER 20565 for details of the only known remaining example of a Second World War floodlight from this experiment in Essex.