Defence Procurement Minister Lord Bach has performed the traditional laying of the keel ceremony for the second of the Astute-class submarines being built by BAE Systems at Barrow-in-Furness.

HMS Ambush will be one of the biggest and most powerful attack submarines ever ordered by the Royal Navy, and joins HMS Astute, which is currently being assembled on the same site.

A third boat, HMS Artful, will follow in due course.

The nuclear-powered Astute-class vessels will have advanced communications systems and a greater capacity for joint operations than existing Swiftsure and Trafalgar class submarines which the Astutes will replace.

Their ability to carry more weaponry will also make them a cornerstone of UK defence capability.

The submarines will displace 7,800 tonnes when submerged, are almost 100 metres long, and will operate with a compliment of 98 officers and ratings..

They have six weapons tubes, used for launching both torpedoes and missiles, and can dive to depths greater than 300 metres.

They are powered by a Rolls-Royce Pressurised Water Reactor 2, equipped with Core H, which is designed to fuel the reactor for the submarine’s entire service life, thereby avoiding the need for costly reactor refuellings.

The first of the class, HMS Astute, is expected to enter service in 2008, and she and her sisters will be based at Faslane on the Clyde, undergoing refits at Devonport.

After touring the Cumbrian yard and meeting members of the workforce, Lord Bach said: “This ceremony marks an important stage in a challenging project.

“The Astute class will be the most advanced and powerful attack submarine the Royal Navy has ever operated, and these boats will play a key part in our defences for decades to come.

“The Royal Navy has a requirement for nuclear-powered submarines well into the future, and the Barrow-in-Furness yard remains the UK’s centre of excellence for submarine building.

“Submarines are extremely demanding engineering projects, and the Astute class is no exception. I am happy to be able to witness this significant project landmark.”

Around 5,000 people are employed on the Astute programme, which is expected to cost the MOD some £3.6 billion.