Question: William John Christopher Vassall, was a British civil servant who spied for the which government nation, under pressure of blackmail from 1954 until his arrest in 1962, the Vassall scandal greatly embarrassed the Macmillan government, but was soon eclipsed by the more dramatic Profumo affair, was a British political scandal that originated with a brief sexual relationship in 1961 between John Profumo, the Secretary of State for War in Harold Macmillan's government, and Christine Keeler, a 19-year-old would-be model?

Context paragraphs:
John Vassall: William John Christopher Vassall (20 September 1924 – 18 November 1996) was a British civil servant who spied for the Soviet Union under pressure of blackmail from 1954 until his arrest in 1962.  Although operating only at a junior level, he was able to provide details of naval technology which were crucial to the modernising of the Soviet Navy.  He was sentenced to eighteen years' jail, and was released in 1972 after ten.  The Vassall scandal greatly embarrassed the Macmillan government, but was soon eclipsed by the more dramatic Profumo affair.

Christine Keeler: Christine Margaret Keeler (born 22 February 1942) is an English former model and showgirl.  Her meeting at a dance-club with society osteopath Stephen Ward drew her into fashionable circles.  At the height of the Cold War, she became sexually involved with a married government minister, John Profumo, as well as a Soviet diplomat.  A shooting incident between two of her other lovers caused the press to investigate her, revealing that her affairs could be threatening national security.  In the House of Commons, Profumo denied any improper conduct but later admitted that he had lied.  This incident discredited the Conservative government of Harold Macmillan in 1963 in what became known as the Profumo affair.

Stephen Ward: Stephen Thomas Ward (19 October 1912 – 3 August 1963) was an English osteopath and artist who was one of the central figures in the 1963 Profumo affair, a British political scandal which brought about the resignation of John Profumo, the Secretary of State for War, and contributed to the defeat of the Conservative government a year later.

Mandy Rice-Davies: Marilyn "Mandy" Rice-Davies (21 October 1944 – 18 December 2014) was a British model and showgirl best known for her association with Christine Keeler and her role in the Profumo affair, which discredited the Conservative government of British Prime Minister Harold Macmillan in 1963.

Scandal (1989 film): Scandal is a 1989 British drama film, a fictionalised account of the Profumo Affair that rocked the government of British Prime Minister Harold Macmillan.  It stars Joanne Whalley as Christine Keeler and John Hurt as Stephen Ward, personalities at the heart of the affair.

The Crown (TV series): The Crown is a biographical drama television series, created and written by Peter Morgan and produced by Left Bank Pictures and Sony Pictures Television for Netflix.  The show is a biographical story about the reign of Queen Elizabeth II of the United Kingdom.  The first season covers the period from her marriage to Philip, Duke of Edinburgh in 1947 to the disintegration of her sister Princess Margaret's engagement to Peter Townsend in 1955.  A second season has been commissioned, which is intended to cover the Suez Crisis in 1956 through the retirement of the Queen's third Prime Minister, Harold Macmillan, in 1963 following the Profumo affair political scandal.

John Profumo: John Dennis Profumo, CBE ( ; 30 January 1915 – 9 March 2006) was a British politician whose career ended in 1963 after a sexual relationship with the 19-year-old model Christine Keeler in 1961.  The scandal, which became known as the Profumo affair, led to his resignation from the Conservative government of Harold Macmillan.

Vassall Tribunal: The Vassall Tribunal was a public inquiry undertaken in 1963 by the British government in the wake of the John Vassall affair.  Vassall, a civil servant working in the Admiralty, had been revealed the previous year to be a Soviet spy, and considerable criticism had been leveled at the security arrangements that were in place.  The tribunal was established to investigate these claims, and determine whether any blame could be laid on officials or ministers.

Profumo affair: The Profumo affair was a British political scandal that originated with a brief sexual relationship in 1961 between John Profumo, the Secretary of State for War in Harold Macmillan's government, and Christine Keeler, a 19-year-old would-be model.  In March 1963, Profumo denied any impropriety in a personal statement to the House of Commons, but was forced to admit the truth a few weeks later.  He resigned from the government and from Parliament.  The repercussions of the affair severely damaged Macmillan's self-confidence, and he resigned as prime minister on health grounds in October 1963.  His Conservative Party was marked by the scandal, which may have contributed to its defeat by Labour in the 1964 general election.

Yevgeny Ivanov (spy): Captain Yevgeny Mikhailovich Ivanov (Russian: Евгений Михайлович Иванов ; 11 January 1926 – 17 January 1994), also known as Eugene Ivanov, was a naval attaché at the Soviet Embassy in London during the early 1960s, and was also engaged in espionage.  His affair with Christine Keeler resulted in another of her lovers, John Profumo, resigning from the United Kingdom government, in what became known as the Profumo affair.

Supporting paragraphs: John Vassall Profumo affair
Answer: Soviet Union