When the calendar showed 16 March 1976, the United Kingdom was shaken by the sudden resignation of its Prime Minister at the time. Harold Wilson announced he could no longer continue leading the country, citing health reasons, and stepped down. This unexpected resignation raised many questions: why did he really resign?

One of the most striking claims was that a secret military coup had been planned against the Labour Party leader. Some even alleged that Britain’s secret intelligence service MI5, a powerful group influencing politics, the economy, and the media (called “The Big Boys”), and even the royal family were involved. At the time, this story didn’t seem very credible — many treated it as a sign that Wilson was experiencing paranoia. But was that really the case?

Five weeks after his resignation, Wilson called two BBC journalists, Roger Courtiour and Barrie Penrose, to his office. He shared his deep concerns from his time in office, believing that MI5 had been running a secret campaign to discredit him. Wilson gave them significant information that he believed showed an anti-democratic agenda within his own government. However, because another political scandal broke at the same time, these allegations were never fully investigated and the truth was not revealed at the time.

Why Was MI5 Alleged to Act?

During the Cold War, the UK was experiencing economic difficulties. Experts warned that the economy was in danger of total collapse. Power cuts were increasing, and people could only work three days a week. Industrial disputes and unrest were rising, and there was widespread unease about the power of left-leaning trade unions. In this bleak environment, many saw communism as the greatest threat. Britain’s elite believed the country was slowly turning communist — and some even convinced themselves that Prime Minister Wilson was a Soviet agent because of this supposed communist threat.

Within MI5, there were suspicions that Wilson was connected to the Soviet Union’s intelligence service, the KGB. Some thought that Anatoliy Golitsyn, a former KGB agent, had groomed Wilson for this role. There was speculation that the previous leader of the Labour Party, Hugh Gaitskell, had been poisoned by the KGB so that the more left-wing Wilson could rise to leadership. The American CIA was also allegedly drawn into these rumors. Wilson’s past visits to the Soviet Union were used as “evidence.”

In the discrediting campaign against Wilson, he was falsely portrayed in the press — including rumors about a secret relationship with his political adviser, Marcia Williams (Baroness Falkender), and claims that both were communists and sympathizers of the Irish Republican Army (IRA). These baseless accusations were spread as part of a psychological propaganda operation. Former MI5 official Peter Wright later acknowledged in his book Spycatcher that security forces conducted an illegal campaign against Wilson out of fear he was a Soviet agent — yet MI5 never found real evidence that he was one.

Even a Military Rehearsal Took Place

One of the main motivations for those who wanted military intervention was the fear of communism. The supposed objective of a coup was clear: to seize the country to prevent communism from taking over. Supporters waited for the right moment to act. The first sign of activity came in 1974, when military units — including tanks — took part in what was described as a “terror exercise” at Heathrow Airport. Wilson’s adviser Marcia Williams later said this seemed like a rehearsal for a possible coup. It was seen as a show of force against the Labour government — so much so that the Prime Minister himself wasn’t even informed about the exercise. In the event of a real coup, the military would first secure Heathrow Airport, the BBC (state television), and Buckingham Palace — and once those points were under control, their dominance would be complete.

The coup plan reportedly involved senior British Army officers and retired commanders, aiming to keep the Labour Party out of power. Adding to the strangeness of the story, the Royal Family was alleged to have given its approval. The plan was that the Queen would issue a public announcement urging citizens to support the military on the grounds that the government could no longer maintain order. There were even plans to detain Wilson and his cabinet in an internment camp. After the coup, Prince Louis Mountbatten was to become temporary Prime Minister.

How Close Did the UK Come to a Military Junta?

Journalist Barrie Penrose, reflecting on Wilson’s fears, said that when asked how close Britain had come to a military government, all he could say was: “We were much closer than anyone realized.” Ironically, in 1979, Britain elected one of its most right-wing governments in history: Margaret Thatcher’s, known as the Iron Lady. Her government went on to severely weaken trade unions and the political left. The Labour Party would not return to power until 1997, under Tony Blair.

Written by: Hussain Kaya — London