When World War II commenced, extensions to the Central Line to the east of London (part of the ‘New Works’ Programme) were incomplete. A five mile section of twin tunnel already completed between Leytonstone and Newbury Park was fitted out as a protected factory for aircraft components.
Plessey’s factory in Ilford had suffered bomb damage and the 3000,000 square feet of underground factory space was completed as alternative accommodation for them in 1942. Up to 4,000 people worked on the site. Items such as shell cases, radio equipment and even components for Bletchley Park were produced there.
After the war, the factory was removed and the tunnels finally opened as the Central Line extension in 1947. An information board about the wartime use is displayed at Redbridge Station.