The UK Royal Navy's third Astute-class attack submarine Artful is undergoing final contractor sea trials ahead of its maiden deployment.
The submarine sailed from Barrow-in-Furness to HM Naval Base Clyde in August last year, and was officially handed over to the Royal Navy in December.
Artful is being tested for its performance and seaworthiness before it is commissioned in mid-March this year.
The trials included the firing of six training variants of the Royal Navy's heavyweight Spearfish torpedo on the British Underwater Testing and Evaluation Centre near the Isle of Skye.
These firings were the most complex of the trials conducted to date, as they required a large number of interconnected systems to function together, which ranged from loading the torpedoes into their tubes, through to the sonar detecting the target and the command system preparing a firing solution.
Artful commanding officer Stuart Armstrong said: "These trials are hugely important as they prove the submarine's primary capability as a weapon system and it gives us the confidence that should we need to fire in anger everything has been tried and tested."
Artful is a nuclear-powered submarine, whose nuclear reactor will not need to be refuelled during its 25-year service life. It can accommodate up to 38 weapons in six 21in torpedo tubes.
BAE Systems Marine Services (BAES (MS)) was contracted to build seven Astute-class submarines for the Royal Navy, which will progressively replace the Trafalgar-class submarines.
HMS Astute and HMS Ambush have already been accepted by Navy Command, while the next two submarines, Audacious and Anson, are currently being built in Barrow, with Agamemnon and an unnamed vessel to follow.
Image: Artful, an Astute Class attack submarine. Photo: courtesy of the Royal Navy.