sentences:  As well as Thatcher's only defeat, it was the last occasion on which a government bill fell at second reading.The defeat was immediately overshadowed by the US intervention in Libya.Thatcher's preference for defence ties with the United States was demonstrated in the Westland affair when, despite ostensibly maintaining a neutral stance, she and Trade and Industry Secretary Leon Brittan allowed the helicopter manufacturer Westland, a vital defence contractor, to link with the Sikorsky Aircraft Corporation of the United States.