In June 2000 a royal protection officer accidentally fired two shots on the royal train while the Queen and Duke of Edinburgh were on board.
The incident occurred in the early hours of the morning when the royals were asleep in another carriage.
In November 2008 one of Tony Blair's bodyguards accidentally fired his gun as the former prime minister prepared to board a flight at Ben Gurion airport in Israel.
No one was hurt in the incident, with the bullet hitting the ground.
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Police have arrested a man wanted in connection with a burglary at the home of pensioner Richard Osborn-Brooks.
The rally comes after it emerged that the Home Office destroyed thousands of landing cards documenting the arrival of windrush-era migrants