🇬🇧 JUST IN: Britain Puts 3 Of Its 4 Nuclear Submarines At Sea Britain has put three Vanguard class nuclear deterrent submarines at sea simultaneously. At least one is carrying nuclear armed Trident II D5 submarine launched ballistic missiles on patrol. Another may be preparing to take over the mission, while the third could be conducting sea trials. This is highly unusual. Only one of Britain’s four Vanguard submarines is normally required to maintain the continuous nuclear deterrent. Having three at sea at once sends a powerful signal of readiness and will be closely watched by both Russia and NATO allies. Britain is making sure its nuclear deterrent remains survivable, operational and ready when it matters most.