The Royal Navy's latest nuclear submarine has been launched by the Duchess of Cornwall, almost four years behind schedule.
The Duchess of Cornwall launched Astute with a bottle of beer
HMS Astute is the first of four new vessels that will be the UK's largest and most powerful attack submarines.
Defence minister Lord Drayson called it "a truly remarkable vessel, and her importance cannot be underestimated".
The £3.5bn programme was dogged by delays and budget overruns, with the government putting in an extra £450m.
Astute was launched at the BAE Systems shipyard in Barrow, Cumbria, which employs about 3,000 people.
ASTUTE FACTS AND FIGURES
Size: 97m (318ft) long, 11.2m (36.7ft) wide, 7,400 metric tonnes (8,157 tons) - 25% heavier and 30% longer than Trafalgar class
Firepower: Six Spearfish torpedo tubes, 38 Tomahawk cruise missiles
Top speed underwater: Undisclosed, but Royal Navy says above 20 knots
Maximum diving depth Undisclosed, but Royal Navy says more than 150m (492ft)
Number of crew: 98 compared with 115 on Trafalgar, with better facilities
Latest technology: Two masts carrying thermal imaging and low-light cameras replace periscope; images can be captured and transmitted to other fleets; advanced sonar
Fuel: Complex pressurised water reactor powers submarine for full service life
Other vessels in class: Ambush, Artful, Audacious
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Dockyard workers, schoolchildren, naval personnel, VIP guests and navy top brass were among the 10,000 visitors who cheered as Camilla launched Astute with a bottle of beer brewed by her crew.
"As an Admiral's wife myself, I am delighted to be in Barrow-in-Furness today for the naming and launching of Astute," she said.
Ron Jones, 58, from the Wirral, is a draughtsman for BAE Systems who was at the launch.
He said: "It's a proud moment when you see it rolling out. I was only a small cog in building it, but you still feel part of it."
Also attending the launch was Carol Jones, 59, also from the Wirral, who said: "It's a fantastic piece of engineering, a national achievement, but I think it looks quite frightening, all in black."
BAE Systems says the project is more technologically complex than the space shuttle.
Each of the four new Astute Class vessels will weigh 7,800 metric tons - equivalent to 1,000 double-decker buses - and be almost 100 metres (328ft) long.
The First Sea Lord, Admiral Sir Jonathon Band, described them as "immensely powerful".
He said: "They will form a key part of our future programme, giving the Royal Navy the versatility and technical excellence needed to operate successfully across the globe in decades to come."
The government signed the Astute contract in 1997 but the first hull sections were not laid until 2001.
Astute will become HMS Astute when it enters service in 2009.
She will create her own oxygen and fresh water from seawater and will be armed with Spearfish torpedoes and Tomahawk cruise missiles capable of hitting a target 2,000km inland.
Along with the three other Astute Class vessels - Ambush, Artful and Audacious - she will be commissioned for 25 years.
It is the first time that the Duchess of Cornwall has launched a vessel.
She was presented with a retriever puppy, as a retriever is on Astute's crest. The puppy will be donated as a guide dog for the blind.