The secret underground railway was built to move letters and parcels underground because the streets of London above were clogged with traffic. It operated from 3 December 1927 until 31 May 2003. There were 23 miles or 37 kms of track and 9 stations. All the trains were driverless and were controlled from the platforms. The carriages were a bit like huge cages. The mail was thrown inside and the lid shut as the trains hurried to their destination. At one time the trains carried 4 million letters and parcels a day! Only one train was designed with seats and this was open at the sides and used for special visitors.

The trains ran in a single tunnel which measured 9 feet across. As the station approached, the tunnel divided into two 7 feet tunnels. In the First World War these huge tunnels became useful for storing important artwork and national treasures in.

In 2003 the railway was ‘mothballed’. This means it was left exactly as it was but closed for use. The Post Office felt it was too expensive to run anymore.

And so a secret unused working railway service does exist beneath the streets of London waiting to be used by those who need it! Level Five didn’t take long to make use of the underground system to help them in their work.