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.
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.
The only thing she would not contemplate was deploying troops on the streets of the mainland.
"If necessary the police should be properly equipped, and even armed, before such a step was taken," the official minute of their discussion noted.
Meanwhile, as the troubles subsided, ministers began to recover their nerve. On July 16 the Cabinet decided it would be a "mistake" to rush through a "modernised form of the Riot Act", ahead of the royal wedding.
There was however some hand-wringing over a traditional Tory bugbear, with ministers complaining of the "deleterious effect on standards of moral and social behaviour" that television was having.
"The fact was that a generation of young people now growing up were habituated to watching television for many hours every day and there was good reason to fear that television had undermined the traditional disciplines of family life, and had given prominence to violence in both news and entertainment programmes," the minutes noted.
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."
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Flick through a slideshow of the Thatcher years:
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