Although the eastern portal of Drewton Tunnel (click here for its full story) has managed to fend-off the dreaded infill, 2,114 yards away, the western end is slowly vanishing. In 1987, its grand approach cutting could still be admired even if a small chalkfall was partly obstructing the entrance. Since then heavy plant has moved in. The top of the portal lurks behind mounds of earth but the casual passer-by would never know what once was there.

The structure’s ovoid profile has a height of between 18ft 5in and 19ft 2in; its width though is consistent at 25 feet. Drewton’s five ventilation shafts each have a diameter of 11ft 6in.