(Pictures 1,2 & 4 © Philip Lindhurst; pictures 3, 5, 6 & 8 © ManOf2Worlds;
picture 7 © Neil Evans)

Built between 1853 and 1857 for the Midland Railway's Bedford-Hitchin line, Old Warden boasts a perfectly straight 882 yard bore lined with blue engineering brick, laying on a downward gradient to the north.

Its line survived the 1963 Beeching cull but the plug was pulled on it one year later. Before the track had been lifted, the tunnel enjoyed a belated moment in the limelight, starring in 'Those Magnificent Men in their Flying Machines'. The short scene involved landing a plane on the roof of a train.