Nuclear sub forced to abandon trials as defect found

Britain's newest nuclear-powered submarine was forced to abandon sea trials and return to port in the Clyde after a system defect was discovered last week.

HMS Ambush – which was handed over to the Royal Navy just last month – was towed back to the Faslane naval base near Helensburgh after coming to an unexpected halt in the middle of Gare Loch on Wednesday.

The £1.6 billion sub, right, was seen to be in difficulties by anti-nuclear campaigners from the Faslane Peace Camp. Crew members were seen standing on top of the vessel, which was venting steam and surrounded by three tugs.

The Ministry of Defence (MoD) has confirmed that the submarine experienced a problem, but declined to give specific details.

Something went wrong that "affected a variety of systems", an MoD spokesman said.

He said: "Following HMS Ambush's maintenance period, undertaken at HM's Naval Base Clyde, an issue with a non-nuclear system was identified. A decision was taken to return it to the base to allow remedial action to take place."

The independent nuclear expert, John Large, said: "The MoD should immediately publish a frank and independent risk assessment.

"We need to know the risks of returning this crippled submarine and its potential radiological impact on nearby Helensburgh and communities further afield. The public deserves to be fully informed if there is any radiological risk and harm deriving from this incident."

Large, who has advised governments on nuclear sub safety, suggested Ambush's propulsion system could have been disabled.

He said: "This would be a completely intolerable event if Ambush was on patrol, during which she is expected to operate at a war footing without need for nearby assistance."

The SNP leader in Westminster, Angus Robertson MP, said he would be demanding details of what happened from the MoD.

"Any incident involving a nuclear submarine is worrying and this is not the first time something alarming like this has occurred in Scottish waters," he said.

Astute Class submarines at Faslane

The second of the Royal Navy's potent new Astute Class attack submarines, sailed into Faslane last week to begin sea trials.

The 7,400 tonne submarine HMS Ambush sailed from the shipyard in Barrow-in-Furness in Cumbria, where she was built.

Minister for Defence Equipment, Support and Technology Philip Dunne said: "Ambush's arrival at her home port to begin her sea trials marks a key milestone in the Astute Class submarine programme and is testament to the skills of those involved in the UK's world class submarine building industry.

"Ambush is an immensely powerful and advanced vessel that will deliver an important capability to the Royal Navy giving it the versatility and technical excellence needed to operate successfully across the globe."

The seven Astute Class boats planned for the Royal Navy are the most advanced and powerful attack submarines Britain has ever sent to sea.

The boat's Commanding Officer, Commander Peter Green, said: "It was very satisfying bringing Ambush into her home port for the first time after initial sea trials.

"The ship's company and I are now looking forward to putting her through her paces over the coming months, ensuring that she is one step closer to being deployed on operations."

HMS Ambush - Nuclear sub sails for sea trials

The Royal Navy's newest nuclear submarine has set sail to begin sea trials.

The second Astute class submarine Ambush set sail from BAE Systems in Barrow-in-Furness, Cumbria.

The 7,400 tonne attack submarine left the site for Her Majesty's Naval Base (HMNB) Clyde, Faslane, which will become its operational base.

This major milestone in the submarine programme is the point at which Ambush will begin to test its range of capabilities, under the control of Ambush Commanding Officer, Commander Peter Green and his crew.

John Hudson, BAE Systems Maritime - Submarines Managing Director, said: "This is the culmination of a tremendous amount of hard work from everyone at BAE Systems, our partners in the submarine enterprise and the hundreds of businesses in our supply chain network.

"Nuclear powered submarines are ferociously complicated, and it would not have been possible to reach the stage we are at today without the valued input of all those highly-skilled people.

"There now follows an extensive and rigorous period of testing during which we're confident Ambush will go on to demonstrate herself as a fantastic capability."

Commander Peter Green, said: "We are grateful to all the people who have worked hard to construct this vessel. The crew cannot wait to start sea trials and take this magnificent vessel a step closer to beginning operations. It is now time to start putting Ambush through her paces on sea trials and prove that this amazing piece of equipment is ready for operations."

Ambush is the second in a planned class of seven submarines and she follows sister vessel HMS Astute to HMNB Clyde, in Scotland, where the first in class has been based since leaving BAE Systems in 2009.

Minister for Defence, Equipment, Support and Technology Philip Dunne said: "Ambush and her sisters are the most powerful and advanced attack submarines ever ordered for the Royal Navy, they are needed by the fleet and they will play a vital role in the future defence of the UK. The completion of Ambush is a tribute to the hard work and commitment of the thousands of people employed in this country's world-class submarine industry."