A FOURTH submarine in the Astute class was officially named at a ceremony in south Cumbria.

The submarine has been called 'Audacious' and was named at BAE Systems' Submarines site in Barrow-in-Furness.

Guests watched as Lady Jones, Audacious' sponsor and wife of Admiral Sir Phillip Jones, the First Sea Lord and Chief of Naval Staff, named the 7,400 tonne, 97-metre-long attack submarine.

In keeping with tradition, she then smashed a bottle of locally brewed beer against her hull.

Tony Johns, managing director of BAE Systems Submarines, said: "We have already delivered three highly-capable Astute class submarines to the Royal Navy and Audacious now takes another significant step towards joining her sister submarines."

Advanced nuclear technology means the Astute class submarines never need to be refuelled and they are able to circumnavigate the world without surfacing.

MORE TOP STORIES:

The submarines manufacture their own oxygen and fresh water from the ocean and are the first class of Royal Navy submarine not to be fitted with optical periscopes, instead using high specification video technology.

Audacious will stay inside the company's main construction facility – the Devonshire Dock Hall – before being launched next year.

BAE Systems is the prime contractor responsible for the design, build, test and commissioning of the seven Astute class nuclear-powered attack submarines.