Specialist divers have cleaned the hull of Britain's newest operational nuclear submarine after she completed her second Mediterranean patrol.
HMS Audacious has been monitoring tankers and cargo vessels, working alongside NATO surface ships on Operation Sea Guardian, from the alliance's base in Souda Bay, Crete, for the last six months.
The security patrols help the alliance to build up a detailed picture of movements in some of the world's busiest shipping lanes.
The fourth Astute-class submarine can stay submerged at periscope depth, taking 360° snapshots day or night, and then return to the depths to pore over the photographs captured at leisure.
When not on Sea Guardian duties, Audacious has been sharpening her anti-submarine warfare skills with the Italian Navy – frigate ITS Carlo Margottini, in particular.
Following half a year of continuous operations, Audacious has had maintenance work at Souda Bay on her hi-tech sensors and boat's systems, as well as the hull, which can get covered with barnacles.
Specialist divers were flown from the UK and ran the entire length of the sub's 97m-long hull with what looks like a huge dental tooth polisher. The precision tool sweeps away barnacles, but not the black tiles which cover Audacious.