lift shafts were dug and before any work on a surface building was done. Legacy The approach road to the station was built and now forms the first part of Hampstead Way. Services began on the CCE&HR on 22 June 1907, running through the abandoned station. The uncompleted platforms and lower passageways remain, with access to the tracks. During World War II these were used to store secret archives with access only available from the cabs of passing service trains. During the Cold War a shaft was dug down to the lower passageways and the abandoned station became part of the London Underground's civil defence preparations. As the tunnels were the deepest in the network it was an ideal site. The role of the control centre was to manage the emergency floodgates placed throughout the tube network at the start of World War II. During this period, the building at the top was disguised as an electricity substation through the appropriate signage. The exits from the platform tunnels are now marked as emergency evacuation routes from the Underground system, and its function is now publicly acknowledged. References External links Abandoned Tube Stations – North End (a.k.a. Bull & Bush) station London Transport Museum Photographic Archive Modern-day tour of North End/Bull and Bush Subterranea Britannica – Bull & Bush – Unopened Northern line Underground Station Infrastructure in London Unbuilt London Underground stations Proposed London Underground stations Abandoned rapid transit stations Railway stations located underground in the United Kingdom