The Royal Family is a prime target for cranks and terrorists, and this was dramatically illustrated in March 1974 when Ian Ball, a former mental patient, tried to kidnap the Princess Royal as she drove up the Mall with her then husband, Captain Mark Phillips. In his attempt to drag the Princess from her vehicle, Ball fired six shots, injuring a police bodyguard, her chauffeur, another policeman and a passer-by.
Ball became the first person to be charged with attempted kidnap of a member of the Royal Family, as well as the attempted murder of Princess Anne's bodyguard. He was detained indefinitely at Rampton secure hospital.
The attack prompted a major overhaul of protection for the Royal Family but no amount of security can completely eradicate the risk.
In 1981, the Mall was the scene of another attack on royalty when Marcus Sarjeant, a carpenter from Folkestone, opened fire on the Queen before she took the salute at the Trooping of the Colour. Millions watching the parade on television saw the Queen struggle to control her terrified horse.
As with the Australian attack yesterday, the shots turned out to be blanks. Sarjeant later told psychiatrists that he pulled the stunt to be famous. He served more than three years in jail for treason.
The Queen is reluctant to adopt US-style security measures such as heavily armed guards and bulletproof cars. Extra officers have been assigned to protect her and the rest of the Royal Family, but there is still a desire to keep precautions as discreet and relaxed as possible.
A year after the Sarjeant attack, Michael Fagan entered Buckingham Palace and reached the Queen's bedroom undetected, despite the installation of barbed wire, additional cameras and other security devices. He sat on her bed chatting to her while police took 10 minutes to answer emergency calls.
Buckingham Palace security came under the spotlight again in July last year when 15 women scaled the perimeter fence, cut the barbed wire and entered the Queen's private gardens in an anti-nuclear protest.
In 1987, Glenn Edwards, 27, was arrested at the Trooping the Colour ceremony armed with a CS gas canister and a cosh. Undercover police officers spotted him among the thousands lining the route. Edwards denied planning an attack.
The risk to royalty is not a new phenomenon. In 1840, Queen Victoria and Prince Albert were shot at by a deranged man. It was the first of seven attempts on her life.Reuse content