IT has been years in the making and is the fourth in class.

But that did not make Audacious, an Astute class submarine built in Barrow, any less impressive a sight.

Audacious, the fourth of seven Astute class attack submarines being built for the Royal Navy, was launched by BAE Systems at its site in Barrow.

Barrow and Furness MP John Woodcock, who has championed Barrow's role in the UK's defence industry, said: “It is always a special sight when a new boat emerges from the Devonshire Dock Hall and Audacious is no exception.

“So much work and craft goes into these boats, making them some of the most complex machines produced anywhere in the world, and seeing them in the open is another reminder of the incredible skill of the workforce of the yard.

“Moments like this are part of the proud tradition of our town and we can all look forward to many more roll-outs in the future as the remainder of the Astute boats and the new Dreadnought class come through.”

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The 97-metre long, 7,400-tonne nuclear-powered submarine which was officially named at a ceremony in December last year, emerged from the site's giant Devonshire Dock Hall yesterday afternoon.

Today it was lowered into the dock water for the first time to begin the next phase of its test and commissioning programme ahead of leaving Barrow for sea trials next year.

Speaking after the launch, Will Blamey, BAE Systems Submarines managing director, said: "Today's launch marks an important milestone in the Astute programme and demonstrates our pride in building submarines for the Royal Navy. Audacious enters the water in a more advanced state of build than any previous Astute class submarine, which puts us in a good position for the next phase of work - the testing and commissioning of her complex systems.

"Designing and building a nuclear-powered submarine is extremely challenging and today's launch is yet another reminder of the unique skills required to deliver such complex programmes. We now look forward to working alongside Audacious' crew to prepare her for sea trials, before she joins her sister submarines in service with the Royal Navy."

Assistant chief of naval staff submarines, Rear Admiral John Weale, said: “It’s an exciting moment to see Audacious enter the water for the first time ahead of trials. Such a feat of engineering is testament to the skills of the BAE Systems workforce in Barrow. As part of an increasingly capable Royal Navy, Audacious will go on to serve on operations right around the world, helping keep Britain safe.”

The boat - which it is forecast will have cost just shy of £1.5bn on completion according to a National Audit Office major projects report - follows the first three in class, Astute, Ambush and Artful.

Those three submarines are now in service, with the final three Astute class submarines at various stages of construction at the yard.

The company is also the industrial lead for the Dreadnought programme, the Royal Navy's next generation of nuclear deterrent submarines. Construction of the first of four submarines, named Dreadnought, began last year.