New Works Programme:
Work began but was interrupted by the outbreak of the Second World War. Track had been laid out and a pair of 980 metre tunnels were partly constructed.
After the war, green belt land was put in place around London and so the land could not be built upon, LU's plan to construct their extension suddenly had no reason to be built.
The completion of the plans were formally cancelled in 1950.
Elstree tunnels became flooded and so the entrances were filled in and buried in the 1970's.
Nothing is visible on the surface.