Newly declassified files reveal that Aneurin 'Nye' Bevan, the celebrated Labour politician and 'father of the NHS,' was monitored by Britain's domestic security service, MI5, for more than 20 years due to suspicions of Soviet sympathies. The surveillance occurred even while Bevan served as a Cabinet minister, according to papers released to the National Archives.

Bevan first came to MI5's attention in the 1930s as a vocal left-wing backbencher, with concerns raised about his associations with prominent communists. An incident in 1934 where Bevan spoke at a rally in Montreal, envisioning a 'united Europe under Soviet rule,' heightened these concerns. Roger Hollis, who later became Director-General of MI5, stated in 1943 that the service did not monitor Members of Parliament unless there was strong reason to believe their actions were motivated by subversive intent.

At one point, MI5's apprehension about Bevan's links to a suspected Russian spy prompted a warning to Prime Minister Clement Attlee. Ironically, one MI5 report concerning Bevan was addressed to Captain A.F. Blunt, who was later exposed as a Soviet spy himself.

MI5 agents continued to track Bevan for decades. A 1954 report detailed a lunch meeting between Bevan and the Soviet ambassador at the Polish embassy in London, which reportedly ended poorly due to communication difficulties arising from Bevan's Welsh accent. Some within MI5 questioned the necessity of monitoring Bevan, with one agent noting in 1943 that Bevan frequently made similar statements in Parliament. Bevan himself reportedly complained in 1956, "They were not spying on Hitler, they were spying on me."

While Bevan himself was never accused of espionage, the files also detail the cases of other individuals, including Labour MP William Owen. Owen, who served for 16 years until 1970, was identified by MI5 as the Czechoslovakian StB spy agency's "most valuable agent in the UK" by 1969. He passed defense secrets, including details of the British Army on the Rhine, to Czechoslovakian handlers in exchange for money, cigars, and wine. The Americans reportedly lodged a strong complaint after discovering the extent of the security breach.

Owen was arrested in January 1970 and faced trial at the Old Bailey. He admitted receiving regular payments but claimed he never divulged anything of significant value. Although acquitted of breaching the Official Secrets Act, Owen was compelled to pay £7,000 in back taxes on his earnings from the spies. Intelligence historian Christopher Andrew suggested Owen was "almost certainly guilty as charged."

The released files also indicate widespread concern within the Labour Party about communist infiltration during the 1960s. Labour leader Hugh Gaitskell reportedly feared that a significant number of his MPs were secretly aligned with the Communist Party of Great Britain. Gaitskell authorized Gordon Walker, his shadow home secretary, to discreetly approach MI5 for assistance in identifying and removing these individuals from the party.

In a 1961 meeting with MI5's deputy director general, Graham Mitchell, Walker presented a list of 25 MPs suspected of communist ties, including William Owen and Tom Driberg. Mitchell conveyed that the leadership's request for MI5's help in purging these members was met with little enthusiasm.

Additionally, the files indicate that the prominent British composer Sir Michael Tippett, known for his pacifism, was monitored by MI5 on suspicion of being a Trotskyist revolutionary. Following the outbreak of World War II, Tippett served a brief jail sentence as a conscientious objector and later composed his anti-war work, 'A Child of Our Time.' An intercepted letter from 1934 revealed Tippett's attempts to engage with a Communist Party organizer. Despite these suspicions, MI5 eventually cleared Tippett, and he was knighted for his contributions to music in 1966.