As the Swiftsure-class submarines aged, the Royal Navy began to design their replacements. The original design called for large submarines designed for blue-water operations. Feasibility studies began in 1986 and were completed by 1989. A design contract was placed with Vickers Shipbuilding & Engineering Ltd. in 1987, but with the end of the Cold War the project was cancelled in 1992. Emphasis switched to the production of a second batch of Trafalgar-class submarines. However the development was extremely slow and initial tenders received from Vickers in June 1995 were too expensive.
Meanwhile, the Royal Navy has changed its submarine-employment strategy from the Cold War emphasis on anti-submarine warfare to the concept of "Maritime Contributions to Joint Operations." The proposed replacement boats were redesigned; the primary mission of the Astute class became direct support of surface forces.
Original plans were for seven boats of the Astute class to replace five Swiftsure-class submarines (Sovereign, Superb, Sceptre, Spartan, and Splendid) and the two oldest Trafalgar-class boats (Trafalgar and Turbulent. Plans, however, have been scaled back. Splendid and Spartan will be left in service, and after the first three Astutes are in service, the option of two additional boats to replace the two Trafalgars will be considered.
On March 17, 1997, an order was placed with Vickers for the first three boats: HMS Astute (S119), HMS Ambush (S120), and HMS Artful (S121). These names were last given to Amphion class submarines that entered service towards the end of World War II.
Under the Smart Acquisition programme, the Astute class is expected to be built roughly one-fifth more quickly than earlier boats, with lower running costs and a much smaller ship’s company.
Astute-class boats will be powered by a Rolls-Royce PWR2 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.
Like all Royal Navy submarines, the sails of the Astute-class boats will be reinforced to allow surfacing through ice caps. They can fire Tomahawk cruise missiles from their torpedo tubes, but not the new "tactical Tomahawk" currently under development, which must be launched vertically.
For more information, see http://www.astuteclass.com/