The UK Royal Navy Trafalgar Class submarine, HMS Trenchant, has rejoined the operational fleet at HM Naval Base Devonport, Plymouth, UK, after completing an extended upgrade.

The upgrades, undertaken by Royal Navy technicians and Babcock Marine in 2009, include a number of improvements to the submarine’s sonar suite and Tomahawk cruise missile capability.

The upgrade will also ensure the submarine’s readiness to meet the UK’s varied commitments.

The submarine crew will soon begin a period of training and testing so they are ready to start operating around the world.