The fourth submarine of the Astute class, built by BAE Systems for the Royal Navy, started marine tests after the delays.
The nuclear submarine HMS Audacious (S122) was planned to go into service in 2018, but this date was delayed to 2021 due to difficulties in the construction of the platform. A total of seven submarines, the Astute class, are being built for the fleet. The first three ships of this class, HMS Astute (S119), HMS Artful (S121) and HMS Ambush (120) submarines serve the Royal Navy.
The Royal Navy say that the 97 metre, 7,400-tonne Astute-class submarines are the most capable submarines ever built for the Royal Navy.
