Video: 'Christine Keeler - Profumo Scandal'

(Wednesday, June 5, 1963; during the Profumo affair and the Cold War) — British Secretary of State for War John Profumo resigned today after acknowledging an extramarital affair with now 21-year-old Christine Keeler (who was also involved with a Soviet spy), and lying to Parliament about it.

Profumo began the affair with the then-19-year-old model in 1961. Profumo denied the affair in a statement to the House of Commons in 1963, but weeks later a police investigation exposed the truth, proving that he had lied in his statement.

Video: 'The Profumo Affair: Sex, Spies, and Scandal During the UK's Cold War'

When the Profumo affair was first revealed, public interest was heightened by reports that Keeler may have been simultaneously involved with Captain Yevgeny Ivanov, a Soviet naval attaché, thereby creating a possible national security risk.

Keeler knew both Profumo and Ivanov through her friendship with Stephen Ward, an osteopath, and socialite who had taken her under his wing.

Video: 'The Profumo Scandal: Fifty years On'

The exposure of the affair generated rumors of other sex scandals and drew official attention to the activities of Ward, who was charged with a series of immorality offenses.

Perceiving himself as a scapegoat for the misdeeds of others, Ward took a fatal overdose during the final stages of his trial, which found him guilty of living off the immoral earnings of Keeler and her friend Mandy Rice-Davies.

Video: 'The Fabulous Sixties: 1963' (Profumo Scandal at 9:07)

The scandal severely damaged the credibility of Macmillan’s government, and Macmillan resigned as Prime Minister in October 1963, citing ill health.

Ultimately, the fallout contributed to the Conservative government’s defeat by the Labour Party in the 1964 general election.