Grounded nuclear sub HMS Astute moored for tests
HMS Astute was towed free at high tide on Friday evening
A nuclear-powered submarine which spent 10 hours grounded off the isle of Skye will remain moored in deep water for days while assessments are carried out.
HMS Astute, the Royal Navy's newest sub, was towed free by a tug on Friday after getting stuck on a shingle bank.
Engineers will determine whether the £1bn vessel can return to its base at Faslane on the Clyde under its own power or if it requires assistance.
Its captain, Commander Andy Coles, from Devon, could now face a court martial.
Experts have launched a detailed investigation, known as a service inquiry, to try to find out why the embarrassing incident occurred.
It will examine how the vessel, which has a state-of-the-art sonar system, found itself in shallow areas of water which are clearly marked.
The investigation will also consider if any crew were negligent and whether the captain should face an inquiry.
A Ministry of Defence spokesman said: "It is inappropriate to comment on possible disciplinary action until a full and thorough investigation has taken place and reported."
The sub is currently moored a couple of miles off the coast, where it will stay for a few days while Navy divers check the hull and rudder for damage.
It was out on sea trials when its rudder became stuck in shallow water close to the Skye Bridge at about 0800 BST on Friday.
It is believed a crew transfer from the shore to the submarine was being carried out at the time.
The vessel was towed free at high tide, at about 1800 BST on Friday. There were no reports of any injuries and the Ministry of Defence said it was not a "nuclear incident".
'Long line'HMS Astute, which was built by BAE Systems in Barrow in Furness, Cumbria, was not expected to enter service until next year.
It weighs 7,800 tonnes, equivalent to nearly 1,000 double-decker buses, and is almost 100 metres (328ft) long.
Its Tomahawk cruise missiles are capable of delivering pinpoint strikes from 2,000km (1,240 miles) with conventional weapons.
The submarine's nuclear reactor means that it will not need refuelling once in its entire 25-year life and it makes its own air and water, enabling it to circumnavigate the globe without needing to surface.
John Ainslie, co-ordinator of Scottish CND, said: "This is just the latest in a long line of incidents involving nuclear submarines off the west coast of Scotland.
"Inquiries into previous incidents have shown an appalling lack of common sense and basic navigation skills on these hi-tech submarines."