Four-minute warningとは 意味・読み方・使い方

The four minute warning was a public alert system conceived by the British Government during the Cold War and operated between 1953 and 1992 when the system was dismantled after the cold war ended. The name derived from the approximate length of time from the point at which a Soviet nuclear missile attack against the United Kingdom could be confirmed and the impact of those missiles on their targets. The population was to be notified by means of air raid sirens, television and radio, and urged to seek cover immediately. In practice the warning would have been more likely to have been three minutes or less.