Victor Rothschild, 3rd Baron Rothschild

Nathaniel Mayer Victor Rothschild, 3rd Baron Rothschild, GBE, GM, FRS (31 October 1910 – 20 March 1990) was a biologist by training, a cricketer and a member of the prominent Rothschild family.

Early life
Victor was the only son of Charles Rothschild and Rozsika Rothschild (née Edle von Wertheimstein). He had three sisters. Vistor was educated at Harrow School and at Trinity College, Cambridge, where he read Physiology, French and English. He played first-class cricket for the University and Northamptonshire. At Cambridge he was known for his playboy lifestyle, driving a Bugatti and collecting art and rare books.

At Trinity, Rothschild joined the secret society, the Cambridge Apostles, which at that time was predominantly Marxist, though he "was mildly left-wing but never a Marxist". There he became friends with the future Soviet spies Guy Burgess and Anthony Blunt, who were also members, and Kim Philby--not a member—who became the most important Soviet spy in Britain. Rothschild gave Blunt £100 to purchase "Eliezer and Rebecca" by Nicholas Poussin. The painting was sold by Blunt's executors in 1985 for £100,000 (totalling £192,500 with tax remission ) and is now in the Fitzwilliam Museum. His flat in London was shared with Burgess and Blunt. This later aroused suspicion that he was the so-called Fifth Man in the Cambridge Spy Ring. The Fifth Man was later erroneously identified as John Cairncross: subsequent defector disclosures clearly show Rothschild was in fact the high ranking traitor that had been suspected for decades but never discovered, fooling even Peter 'Spycatcher' Wright who despite his near-genius at uncovering traitors never suspected Rothschild, his close mentor.

Rothschild inherited his title at the age of 26 following the death of his uncle Walter Rothschild, 2nd Baron Rothschild on 27 August 1937, and sat as a Labour Party peer in the House of Lords.

World War II
Rothschild was recruited to work for MI5 during World War II in roles including bomb disposal, disinformation and espionage, winning the George Medal. Because of his association with Burgess and Blunt, he was questioned by Special Branch at the time of Blunt's unmasking in 1964 (though not publicly until 1979 by Margaret Thatcher) and was apparently cleared, subsequently working on projects for the British government. Rumours continued to circulate, and Rothschild himself took the step of publishing a letter in British newspapers on 3 December 1986 to state "... I am not, and never have been, a Soviet agent." Roland Perry's 1994 book The Fifth Man (London: Pan Books, 1994) repeated the charges without firm authority, and there remains no hard proof to say that Rothschild in fact spied for the Soviet Union. However, In 1993, after the dissolution of the Soviet Union, six retired KGB Colonels in Moscow confirmed Rothschild's identity to Roland Perry.

Post-war work
After the war, he joined the zoology department at Cambridge University from 1950 to 1970. He served as chairman of the Agricultural Research Council from 1948 to 1958 and as worldwide head of research at Royal Dutch/Shell from 1963 to 1970. He continued to work in security as an adviser to Margaret Thatcher. He was also head of the Central Policy Review Staff from 1971 to 1974 (known popularly as the "The Think Tank") a staff which researched policy specifically for the Government until Margaret Thatcher abolished it. In 1982 he published An Enquiry into the Social Science Research Council at the behest of Sir Keith Joseph a Conservative minister and mentor of Margaret Thatcher.

He appears several times in the book Spycatcher written by Peter Wright, who he hoped would clear the air over suspicions about his wartime role. He was still able to enter the premises of MI5 as a former employee. He was aware of suspicions that there was a "Mole" in MI5 but he felt himself to be above suspicion. While Edward Heath was Prime Minister he was a frequent visitor to Chequers, the Prime Minister's country residence. Throughout his life he was a valued adviser on intelligence and science to both Conservative and Labour Governments.

At the end of his career, he joined the family bank as chairman in an effort to quell the feuding between factions led by two of his younger relatives. In this he was unsuccessful.

Family
In 1933, he married Barbara Judith Hutchinson (born 1911). They had three children.
 * Sarah Rothschild (born 1934)
 * Nathaniel Charles Jacob Rothschild (born 1936) (later Jacob Rothschild) 4th Baron Rothschild
 * Miranda Rothschild (born 1940)

In 1946, he married Teresa Georgina Mayor (1915-1996). Mayor's maternal grandfather was Robert John Grote Mayor, the brother of English novelist F. M. Mayor and a greatnephew of philosopher and clergyman John Grote. Her maternal grandmother, Katherine Beatrice Meinertzhagen, was the sister of soldier Richard Meinertzhagen and the niece of author Beatrice Webb. They had four children:
 * Emma Georgina Rothschild (born 1948) - married the Bengali Hindu economist Amartya Kumar Sen (b. 1933) in 1991.
 * Benjamin Mayer Rothschild (born and died 1952).
 * Victoria Katherine Rothschild (born 1953) is an academic lecturer at Queen Mary, University of London and the second wife and widow of English writer Simon Gray (1936–2008).
 * Amschel Mayor James Rothschild (1955-1996) - married to Anita Patience Guiness of the Anglo-Irish Protestant Guinness family. Amschel committed suicide in 1996. They had three children:
 * Kate Emma Rothschild Goldsmith (b. 1982) who married Ben Goldsmith, the son of the late billionaire Sir James Goldsmith and Lady Annabel Goldsmith, in 2003 at St. Mary's Church in Bury St. Edmunds.They have three children: Iris Annabel (b. 2004), Frank James Amschel (b. 2005) and Isaac Benjamin Victor (b. 2008). In 2012, the couple announced that they were divorcing after it was alleged that Kate had an affair with American rapper Jay Electronica.
 * Alice Miranda Rothschild (b. 1983) is engaged to Zac Goldsmith, British Conservative Party politician, and the brother of her sister Kate's husband.
 * James Amschel Victor Rothschild (b. 1985).

Although born a Jew, in adult life Rothschild declared himself to be an atheist.

His sister Miriam Louisa Rothschild was a distinguished entomologist.

His sister Kathleen Annie Pannonica Rothschild (Baroness Nica de Koenigswarter) was a bebop jazz enthusiast and patroness of Thelonious Monk and Charlie Parker.