Thanks to how the tube network was built by the early private entrepreneurs, there are dotted around the place a fair number of disused shafts and tunnels which attract the curious minds – and occasional physical visits.
Although South London has but a few tube lines, and they are as scarce as a black cab after midnight, there is still the odd bit of abandoned tunnel even south of the river. One such tunnel is also comparatively modern, having been dug in the early 1970s, then abandoned after just a couple of years.
A short stretch of tube tunnel that leads from nowhere to nowhere, next to the East London Line but not connected to it, this was an experimental tunnel dug as part of the original Fleet Line plans.
As tube history fans will be aware, most of the original plans to extend what is now called the Jubilee Line involved a line running through the city of London and over towards Wapping, then down through the East London Line tunnel, and then variously either towards Lewisham, or over towards Thamesmead via the Isle of Dogs.
Being fairly sure where the Fleet Line would run, they decided to build one short stretch of the future tunnel in order to test how the recently invented Bentonite Shield would work in the softer water logged soils of South London without using compressed air.
The length of tunnel driven was 144 meters, from a hexagonal shaft that was 19.6m deep. The tunnelling machine was delivered to the site on 12 December 1971, and the first drive attempt took place on 24 February 1972.
As we know, the Fleet Line extension was never built as planned at the time, and later the renamed Jubilee Line skirted round South London and to the northern end of the Isle of Dogs. But that early stretch of tunnel is still there under the New Cross streets - abandoned, covered up and largely forgotten.
This is roughly where the tunnel starts – deep under this railway bridge.
And here is the other end – somewhere under this sealed off yard.
Although the experimental tunnel itself lead nowhere, it does have a heritage, as it proved the viability of the Bentonite Shield, which is still used – in modified versions – when tunnelling through water soaked soils.