HMS Monmouth is back at sea after an 18-month refit in Plymouth.

The Royal Navy frigate left HM Naval Base Devonport on Friday 12th June having spent a year and a half being upgraded with cutting edge technology.

Known as the "Black Duke" after James Scott, the Duke of Monmouth, the ship and her crew has left port for sea trials, before going back into active service.

Commander Philip Tilden, captain of HMS Monmouth, said: "It is important not to underestimate the monumental and complex effort put in by both my ship's company and our industrial partners to get the ship to sea today after such an extensive refit.

"In particular, at this significant milestone my team in the 'Black Duke' can be very proud that the huge personal investment they have made to date will ultimately benefit our nation for many years to come." 

HMS Monmouth entered refit at the beginning of 2014 and has seen a significant amount of structural work to her superstructure, which has included approximately 17 tonnes of new steel covering an area of 220 square metres and over 1.1km.

The focus will now move to testing the ship's engines, as well as trialling the latest updates to her weapons and computer systems; including the new Type 997 medium range radar, 4.5 inch gun and Seawolf missile system.

Lieutenant Commander James Holgate, the ship's weapon engineer officer said: "Having brought Monmouth into refit over 18 months ago it is a real honour to finally get the chance to reap the benefits of the hard work put in by all."

Following a significant changeover of personnel, more than 90 per cent of the ship's company will be sailing with the Type 23 frigate for the first time, with approximately 30 per cent making their maiden voyage.

HMS Monmouth will spend the next few months conducting her sea trials before undertaking training and endorsement which will get her ready to be deployed on operations whenever and wherever tasked.