English: Pictured is an Officer of the watch aboard HMS Vanguard.

The Royal Navy has operated the UK’s Continuous at Sea Deterrent since 1967 when the first SSBN – or Ship Submersible Ballistic Nuclear – HMS Resolution began patrolling armed with the Polaris missile system.

In 1996 HMS Vanguard, the first submarine armed with the Trident missile system, arrived on the Clyde and took over deterrent patrol duties from the Resolution Class. The four Vanguard-class submarines form the UK's strategic nuclear deterrent force.

Each of the four boats are armed with Trident 2 D5 nuclear missiles. Like all submarines the Vanguard Class are steam powered, their reactors converting water into steam to drive the engines and generate electricity.

Fitted with world beating sonar, essentially their ears, the system is so sensitive they can hear vessels over 50 miles away.

• Organization: Royal Navy
• Object Name: 04130598
• Category: MOD
• Supplemental Categories: People, Royal Navy, Equipment, Submarines, Ballistic
• Keywords: Royal Navy, Personnel, Non-Identifiable, Submariner, Movements, Standing, Equipment, Submarine, Ballistic, Strategic Nuclear Deterrent Force, SSBN, Vanguard Class, Trident, HMS Vanguard, S28, Blue Sky, Map, Compass, Conning Tower
• Country: At Sea