Prime minister Margaret Thatcher secretly discussed issuing firearms to the police amid fears riots could disrupt the wedding of the Prince of Wales and Lady Diana Spencer, according to official papers made public for the first time.
Files released by the National Archives in Kew, west London, under the 30-year rule show the Metropolitan Police Commissioner was so concerned about the security situation he even raised it with the Queen.
In 1981, Mrs Thatcher's Conservative government was rocked by the worst outbreak of civil unrest since Victorian times as rampaging youths battled the police in cities across England.
During the spring and summer, an explosive cocktail of inner city deprivation, rising unemployment, racial tensions and resentment at police tactics reached boiling point.
After riots erupted in Brixton, south London, in April, a fresh wave of disturbances broke out at the beginning of July - the month of the royal wedding - centred on Toxteth in Liverpool.
In nine days of rioting, one person died after being struck by a police vehicle, 468 police officers were injured, 500 people were arrested and 70 buildings were damaged so severely by fire they had to be demolished.
As police used CS gas for the first time on the British mainland to try to quell trouble, further riots broke out in other cities, prompting fears of widespread breakdown of law and order.
After visiting the scene of the disturbances in Toxteth and Moss Side in Manchester, Home Secretary William Whitelaw warned Mrs Thatcher that "emergency legislation could not be ruled out".
The prime minister quickly agreed the police should have all the additional equipment they needed - including water cannon and rubber bullets or baton rounds - with army camps being set aside to hold offenders if the prisons could not cope.
In the event the "fairytale" wedding of Charles and Diana passed off without trouble in a sea of pageantry and patriotism which, for many in the country, eclipsed the shocking events of the preceding weeks. A jubilant Bernard Ingham, the prime minister's press secretary, informed her: "The triumph of the royal wedding has been a national tonic."