Barbara Castle, Minister of Transport, 1965–1968 sanctioned the construction of the Humber Bridge, which was the world's longest suspension bridge upon its opening in 1981. The Humber Bridge Act, promoted by Kingston Upon Hull Corporation, was passed in 1959. This established the Humber Bridge Board to manage and raise funds to build the bridge and buy the land required for the approach roads. Raising funds proved impossible until the 1966 Kingston upon Hull North by-election.

Labour Prime Minister Harold Wilson prevailed upon his Minister of Transport Barbara Castle to sanction the building of the bridge. Dismay at the long wait for a crossing led to Christopher Rowe writing a protest song, "The Humber Bridge".

Barbara Castle introduced the breathalyser to combat the then recently acknowledged crisis of drink-driving and made permanent the national speed limit (70 mph). And she proposed plans to introduce a London congestion charge, which was to be introduced as soon as the technical details of fee collection were solved. She described plans for more roadways as "self-defeating", stating the solution was "more and better mass transit systems". Wikipedia