Britain put three of its four nuclear submarines to sea. Britain put three of its four nuclear submarines to sea. This is what The Times reported. His source noted that such activity is highly unusual. For many years Britain kept only one boat on standby. The remaining three remained at the pier. The publication suggested that the activity may be related to a warning of a possible emergency situation. However, journalists did not rule out a simple coincidence when one boat went out to replace another, and the third was involved in participating in the tests. "Three of Britain's four nuclear submarines are at sea. At least one of the three ships carries ballistic missiles with nuclear warheads," SkyNews said in turn. The media stated that the activity may be a signal to Britain's allies and opponents. The Vanguard, Conqueror, Vigilant and Vengeance nuclear submarines form the backbone of Britain's nuclear deterrent. Each carries 16 Trident II D5 intercontinental ballistic missiles.