Codes were visible from the air, with 10-foot (3.0 m) high letters displayed alongside the Signals Square and Watch Office, usually near the control tower.
[6] During wartime the red beacon became a familiar marker for returning bomber crews, signalling the end of a mission.
Instead a mobile light was placed at one of three positions some distance from the airfield and a different wartime code was used: Elmdon (EK) used JD / KJ / UT in war, Ringway (EZ) used CL / HV / JL.
The beacon light itself consisted of eight 400 watt red neon tubes mounted in a glass pyramid lamp house.
[15] Pundit Lights were part of the cargo of the SS Thistlegorm, a Merchant Navy ship sunk in the Red Sea in 1941, whilst en route to the Western Desert Campaign in Egypt.
A later, two-wheeled Pundit Light on a standard 0.75-long-ton (760 kg) Sankey trailer chassis is preserved at the Norfolk & Suffolk Aviation Museum, Flixton.
Like the Pundit Light, they were also trailer-mounted with a generator set, but used a single continuous white lamp with the flashing provided by rotating shutters.