First transmitted in 1969, this documentary follows the construction of the world’s most advanced underground system. Macdonald Hastings narrates the story of one of the most complex tunnel engineering feats of its time. He reveals the isolation felt by the miners who spent six years burrowing deep beneath the streets of London, shows what they did beneath one of London's most famous department stores and explains why the ground at Tottenham Court Road had to be frozen during the hottest weeks of 1966. The result is a brave new world of transport with automated trains, two way mirrors, automatic fare collection and closed-circuit television, all choreographed by a computer programme played out by an updated version of a pianola located in a control room somewhere near Euston station.

• Documentary