For every London Underground station we take for granted to get us from A to B, there are numerous others that have been closed or abandoned, and many more that were planned but never actually built.
Many fledgling plans for stations were put forward in the late 1900s, as rival companies fought to set-up new lines and compete for markets in the early days of the Underground. But other plans date from the Art deco glory days of the Underground in the 1930s. One such plan was known as The Northern Heights scheme - a grand plan to expand the Underground to the north of the capital by bringing together a web of existing London and North Eastern Railway (LNER) overground lines north of Highgate.
The plan was to extend the existing lines to include London's northern hills - with routes from Edgware to Bushey Heath, a section from Mill Hill East to Edgware, and a line from Finsbury Park to Alexandra Palace with an interchange linking it to the Northern Line at Highgate. Some new sections would be built and some existing overland routes electrified.
One of them, that is rarely talked about, was supposed to be called Elstree South. Today this is basically exactly where Junction 4 of the M1 is located. It was thought that by bringing the Underground to the area it would help to generate the house-building in this rural part of London, and in turn that would provide passengers for the Underground.
A big new depot was also to be created near the station at Aldenham to house the Class 38 trains that would be used on the Northern Heights plan. Elstree South station was to be located in a cutting with the platforms immediately north of the entrances for a pair of 1,575-foot long tunnels through the hillside towards Brockley.
Immediately north of the station were to be the junctions to the new depot, and a pair of depot sidings would have occupied the station cutting on the south side. The station building, designed by Charles Holden, would have had a statue of a Roman Centurion at one end inspired by the nearby site of the Roman settlement of Sulloniacae. This was a kind of ancient service station where staff working for the Roman postal service (Cursus Publicus) could change horses and rest overnight.
Located at the point where northbound trains exited the tunnel under Brockley Hill, Elstree South's station entrance building would have been on the main road itself, although which side it would have been on is debated. Indications for the early designs point strongly to the north side.
As part of the station works, the road in front of the station, Elstree Hill (now Elstree Hill South), was to be widened to 100 feet (30 m) to accommodate a planned trunk road improvement scheme for the A5 road (now renumbered the A5183 at this point).
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Construction work on the Northern Heights project did begin in the late 1930s, but the Second World War put a stop to everything. Work between Edgware and Bushey Heath had actually started in June 1939. The route of the line had been cleared and laid out, and some earthworks and tunnelling carried out between Edgware and Elstree South. But in September 1939 on the outbreak of war, this work was halted and was ended permanently in the December as all the funding was pumped into the war effort.
During the war years, the LPTB-owned land was used for farming vegetables and the depot buildings were used to build Halifax bombers. After the war through, new schemes to protect the Green Belt land to the north of London were brought in. This would mean that the new homes that would have provided the passengers for the Northern Heights lines were unlikely ever to get built. The Northern Heights plan was shelved forever in 1950.
The tunnelling shields being used to dig the tunnels were removed in 1949 and the tunnels sealed. The entrances were finally buried in the 1960s when the M1 motorway was constructed and today nothing is visible on the surface.
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