Dieter Felix Gerhardt (born 1 November 1935) is a former commodore in the South African Navy and commander of the strategic Simon's Town naval dockyard.

He was convicted of high treason as a spy for the Soviets for a period of twenty years in South Africa together with his second wife, Ruth, who had acted as his courier.

[9] British journalist and security services specialist Chapman Pincher maintained that, while in London in the late 1960s, Gerhardt was able to interview Royal Navy Polaris submarine crews for potential candidates that the Soviets could approach.

[12] In 1973, Gerhardt married his second wife, Ruth Johr, a Swiss citizen who author Chapman Pincher claims was already a spy for the German Democratic Republic.

In this position, he had access to all the South African Naval intelligence reports from the Silvermine listening post near Cape Town,[19] as well as technical details of weapons systems.

[6][21] Admiral of the Fleet Lord Hill-Norton publicly contradicted this view, but supported screening of Royal Navy officers who had been in contact with Gerhardt throughout his career.

[24][page needed] Gerhardt's cover was finally blown by Soviet double agent Vladimir Vetrov (given the codename "Farewell" by France's DST intelligence service[25])[26][27] He was arrested at his hotel in New York City in January 1983 in a sting operation by the Federal Bureau of Investigation while he was taking a degree in mathematics at Syracuse University.

[30] Following his deportation to South Africa, Gerhardt and his wife were tried in camera in the Cape Town Supreme Court, with the prospect of a death sentence being handed down for high treason.

[22] In his trial, Gerhardt stated that the repulsion he felt towards his father's right-wing political beliefs drove him to fight apartheid by serving the USSR.

[14] In 1988, she attempted to gain her freedom by renouncing violence, and thereby take advantage of an offer made by PW Botha to political prisoners like Nelson Mandela, however the request was turned down by Justice Goldstone.

He was visited in prison on 22 January 1992 by a delegation from the ANC, who were seeking information regarding the SADF that might have assisted them in CODESA negotiations with the National Party government.

[1][5][32][37][36][a] Former Minister of Defence Magnus Malan said that the former spy's release was a precondition to the restoration of diplomatic ties and the signing of a trade agreement between South Africa and the Russian Federation.

[45] In February 1994, he told Des Blow of the Johannesburg City Press that the Vela incident was the result of a joint Israeli-South African nuclear test, code-named Operation Phoenix.