The Astute-class submarines are the next-generation nuclear fleet submarines of the UK Royal Navy.

They will have massively increased firepower compared with earlier attack submarines and can dive to depths in excess of 300 metres with a complement of 98 men.

Replacing the five Swiftsure Class submarines, launched between 1973 and 1977 and approaching the end of their operational life.

Astute-class boats are powered by a Rolls-Royce PWR2 (Core H) reactor and fitted with a pump-jet propulsor. The PWR2 reactor was developed for Vanguard-class ballistic missile submarines. As a result Astute-class boats are about 30 per cent larger than previous British attack submarines, which were powered by smaller reactors.

With improved communications, a greater capacity for joint operations and the ability to carry more weaponry, the Astute-class submarines will become a cornerstone of UK defence capability until at least 2035.

The Astute will be equipped with the Tomahawk Block IV (Tactical Tomahawk) cruise missile from Raytheon fired from the 533mm torpedo tubes.

Astute will have six 533mm torpedo tubes, and will be equipped with Spearfish torpedoes and mines. There is capacity for a total of 36 torpedoes and missiles.

The Astute submarine programme is expected to have a total cost to the UK MoD of about £3.5 billion. Around 5,500 people are employed on the project for the first three Astute class submarines.

Orders for the procurement of further Astute boats are being considered and according to the UK MoD, announcements will be made at the appropriate time. Astute class submarines will be based at Faslane on the Clyde and will undergo refits at Devonport. The first is due in service in