Britain immediately put to sea three of the four nuclear submarines capable of carrying nuclear weapons. The Times. Normally, only one Vanguard class submarine is in combat service. According to the publication, such a large deployment of the British submarine fleet took place for the first time in more than five years. Apparently, one of the submarines is carrying nuclear weapons and conducting routine patrols, the second is preparing for its next deployment, and the third is undergoing sea trials. The fourth submarine available to the British Armed Forces was unable to take part in the deployment, as it is currently undergoing maintenance.