The UK Ministry of Defence has awarded BAE Systems a contract worth £1.2-billion for Audacious, the fourth submarine in the Astute class. The full contract covers the design, build, test and commissioning programme. First steel was cut in 2007 and Audacious is at an advanced stage of construction at BAE Systems’ site in Barrow-in-Furness, Cumbria.

BAE Systems Maritime, Submarines Managing Director John Hudson said: “This is a very significant milestone for the company as it provides increased stability for the remainder of the programme.

“The Astute class will deliver to the Royal Navy a fantastic attack submarine capability and both HMS Astute and Ambush are currently demonstrating this while on their sea trials. Audacious, and the rest of the submarines in the Astute class, will eventually complement those already at sea.”

The MoD also confirmed today that a further £1.5 billion has been committed to the Astute programme for the remaining three submarines in the class, which includes early build work on boat 5, Anson, whose keel was laid in October, 2011.

Audacious will include a number of design changes to the first three submarines in the Astute class. Most relate to the submarine’s combat system—primarily its command, navigation and sonar systems.

The 97-metre-long Astute class submarines boast a range of world-class capabilities. Powered by a sophisticated nuclear propulsion system, the reactor never needs refuelling. The sonar system has the processing power of 2,000 laptops and can track ships 4,800 kilometres away. Armed with both Tomahawk land attack missiles and Spearfish torpedoes, its missiles have a target range of 2,000 kilometres with accuracy measured in metres.