Plot to assassinate Queen Elizabeth II during 1983 U.S. visit revealed by FBI docs

There was a potential threat to assassinate Queen Elizabeth II during her 1983 trip to the United States.

Documents detailing the murder plot were released this week on the FBI’s records website. Britain’s longest-reigning monarch died in September after a 70-year reign. She was 96.

The late monarch’s West Coast visit with her husband, Prince Philip, included a stop in San Francisco. At the time, the queen and the Duke of Edinburgh were invited by President Ronald Reagan to see his home state of California.

The FBI said a San Francisco police officer who frequented a bar favored by sympathizers of the Irish Republican Army had received a phone call. It was from an unidentified patron who claimed his daughter had been killed in Northern Ireland by a rubber bullet.

QUEEN ELIZABETH II, LONGEST-REIGNING BRITISH MONARCH, DEAD AT 96

According to the documents, the man said he was going to "attempt to harm Queen Elizabeth" by either dropping an object off the Golden Gate Bridge onto the queen’s royal yacht or try to kill her during a visit to Yosemite National Park. It noted that the Secret Service planned to close the walkways on the Golden Gate Bridge when the ship drew near.

The royal visit to the U.S. came during the Troubles, the 30-year conflict in Northern Ireland, People magazine reported. It divided unionists and nationalists over whether Northern Ireland should stay within the U.K. or join the Republic of Ireland, the BBC noted. 

According to the outlet, groups from both sides carried out attacks, and British troops were deployed to Northern Ireland. Over 3,500 people were killed during the conflict.

Philip’s uncle, Lord Louis Mountbatten, was assassinated by a bomb in 1979. The Troubles ended in 1998 after the Good Friday Agreement was signed.

The royal couple arrived on the Royal Yacht Britannia. They spent a week in California. 

The 56-year-old queen arrived with an entourage of about 40 people, The New York Times reported. She was accompanied by several ladies-in-waiting and her private secretary, Sir Philip Moore. The outlet said the former sound stage of "M*A*S*H" was transformed into a setting for a party of 500 guests.

The names of both the officer and the caller were redacted in the documents, which did not indicate whether precautions were taken at Yosemite or whether any arrests were made. A March 7, 1983, memo indicated the queen completed the U.S. visit "without incident" and that "no further investigation is warranted."

The documents also detailed other security concerns involving the queen’s visits to various U.S. cities.

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Before the queen visited Kentucky in 1989, the FBI noted that "the possibility of threats against the British monarchy is ever present from the Irish Republican Army." 

When the queen attended a Baltimore Orioles game with President George H.W. Bush in 1991, several dozen demonstrators in the park chanted slogans condemning Britain’s policy in Northern Ireland.

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The queen’s eldest son, King Charles III, was crowned May 6.

The Associated Press contributed to this report.