We don´t know exactly where the underground tunnels were dug, but we do know they were found.

It is understood the tunnel was dug at the end of the first stage of construction of the Crossrail tunnels at the time of the Second World War.

The tunnels are still being excavated.

Crossrail is set to open in 2018.

The tunnel, which will have up to 300 feet of underground passageway, was dug in the early 1960s at a time when tunneling was not yet being considered as an option.

However, the tunnel will still be used for construction of Crossrail trains.

CrossRail has been touted as one of the most exciting public transport projects in the country.