In July 1961, at a party at Cliveden, home of Viscount Astor, Profumo met Christine Keeler, a model with whom he began a sexual relationship. Profumo ended it after only a few weeks but rumours about the affair began to circulate. Since Keeler also had sexual relations with Yevgeny Ivanov, the senior naval attaché at the Soviet Embassy, the "Profumo Affair" took on a national security dimension.
In December 1962, a shooting incident in London involving two other men who were involved with Keeler led the press to investigate Ms Keeler, and reporters soon learned of her affairs with Profumo and Ivanov. But the British tradition of respecting the private lives of British politicians was maintained until March 1963, when the Labour MP George Wigg, claiming to be motivated by the national security aspects of the case, referred in the House of Commons (ie. under immunity from any possible legal action) to rumours that Profumo was having an affair with Keeler. Profumo then made a personal statement in which he admitted he knew Keeler but denied there was any "impropriety" in their relationship.
Profumo`s statement did not prevent newspapers publishing stories about Keeler, and it soon became apparent to Macmillan that his position was untenable. On 5 June 1963 Profumo was forced to admit that he had lied to the House, an unforgivable offence in British politics. He resigned from office, from the House and from the Privy Council. Before making his public confession Profumo confessed the affair to his wife, who stood by him. It was never shown that his relationship with Keeler had led to any breach of national security. The scandal rocked the Conservative government, and was generally held to have been among the causes of its defeat by Labour at the 1964 election.
Profumo maintained complete public silence about the matter for the rest of his life, even when the 1989 film Scandal and the publication of Keeler`s memoirs revived public interest in the affair.