THE Ministry of Defence has refused to reveal official safety ratings for the Trident nuclear weapons system and nuclear-powered submarines on the Clyde, citing "national security".

The annual ratings, and the reports that justified them, were published for ten years by the MoD, uncovering a series of concerns about spending cutbacks, staff shortages and accidents. But now ministers have clamped down and decided that they can’t release any findings at all on security grounds.

Experts have accused the MoD of trying to evade public scrutiny, hide “cock-up and incompetence” and endanger public safety. But the MoD has insisted that the secrecy had not prevented independent assessment of the nuclear programme, which met “all the required standards”.

Safety during the refurbishment, transportation and storage of Trident nuclear warheads, along with the operation of the UK reactor-powered submarine fleet based at Faslane near Helensburgh, is regulated by the Defence Nuclear Safety Regulator (DNSR). Unlike the civil nuclear power industry, which is overseen by the independent Office for Nuclear Regulation, DNSR is part of the MoD.

After a prolonged freedom of information battle, the MoD started publishing DNSR annual reports from 2005. They were released over ten years until 2014-2015, highlighting issues as “regulatory risks” 86 times, including 13 rated as high priority, 50 as medium priority and 23 as low priority.

One of the issues often rated by DNSR as a high risk was a growing shortage of suitably qualified and experienced nuclear engineers. The report for 2014-15 warned that the lack of skilled staff was “the principal threat to the delivery of nuclear safety”.

It also cautioned that “attention is required to ensure maintenance of adequate safety performance” for ageing nuclear submarines. Similar concerns were highlighted in DNSR reports for 2013-14, 2012-13 and previous years.

The 2007 report flagged up 11 "potentially significant risks" at military nuclear sites, and the 2006 report warned that "crew fatigue" could cause hazards during the transport of nuclear warheads by road.

In November 2018 the Sunday Herald revealed that the MoD had abruptly decided to stop publishing the annual DNSR reports to protect national security. Last week the defence minister, Guto Bebb, went further, refusing to give any indication of even the headline summaries of the reports covering the last three years.

Labour’s defence spokesperson, Fabian Hamilton, asked the MoD “what category of safety assurance was assigned to the nuclear domain by the Defence Nuclear Safety Regulator for the years 2015-16, 2016-17 and 2017-18”.

Bebb confirmed that DNSR reports for those years contained “the level of safety assurance”, but insisted they “will not be published as it has been assessed to do so would impact national security”.

He added: “This does not prevent the effective management and independent assessment of the defence nuclear programme, nor prevent its duty holders being held to account, but in the current security climate we cannot accept compromising our capabilities by disclosing the reports or details contained within.”

The Scottish National Party attacked the MoD’s secrecy. “This is simply not good enough and the MoD have a bad track record on transparency,” said the party's defence spokesperson, Stewart McDonald MP.

“Safety and security are paramount when it comes to anything nuclear – and we need to be confident that is always the case.”

The independent nuclear engineer, John Large, described national security as a “flimsy excuse” for hiding nuclear safety issues. He suggested that the four Vanguard submarines that carry Trident warheads will all have to be brought into dock for unplanned overhauls because of problems with the ageing reactors that drive them.

“There is good reason to believe that both human resource and technical issues are continuing to impact on the reliability and full strength deployment of both the hunter-killer and Vanguard nuclear-powered submarines,” he said.

“The suppression of if and how the Royal Navy is reaching its nuclear safety targets is of great concern because within the MoD’s hierarchal review structure there is no opportunity for independent assessment. In effect, the buck stops short of a faceless admiral, whose primary duty of providing the nuclear deterrent overrides the safety of the public at large.”

Large argued that it was becoming increasingly difficult to determine how many “skeletons are accumulating in DNSR’s hideaway cupboard”. He accused the MoD of losing “effective control” over its nuclear submarine maintenance and refuelling programme.

“DNSR is simply failing to keep up with nuclear safety issues,” he added. “Probably what this secrecy is hiding is cock-up and incompetence that, by all unofficial accounts, is growing within a unacceptable environment of unaccountability.”

Professor Andy Stirling, a nuclear expert from the University of Sussex, warned that secrecy could hide public dangers. “The British military nuclear establishment is increasingly seeking to escape public scrutiny and democratic accountability," he said.

“The MoD is using the trump card of security to quash reasonable questions. History shows how dangerous this state of affairs can be, and how essential it is to achieve healthy transparency.”

The Nuclear Information Service, which monitors the nuclear weapons programme, called on MPs to demand operations be halted unless they can be proved safe. “If the MoD cannot give the public basic guarantees about the safety of their nuclear warheads and nuclear submarines, then the obvious conclusion is that safety issues are being hidden from the public,” said the service’s director, David Cullen.

“No responsible nuclear operator would behave in this cloak and dagger fashion. Parliament should step in and call for a halt any activities where the public cannot be given nuclear safety assurances.”

The SNP MP for Edinburgh North and Leith, Deidre Brock, thought the MoD’s behaviour “beggars belief” and demanded the DNSR reports be published. “A sudden shift from openness to secrecy suggests that something is going wrong and it leaves me wondering whether there is something serious that we are simply not being told about,” she said.

“Are the Tory cuts now biting so deep that operational safety around nuclear weapons is compromised? Have there been mistakes, accidents and near misses that ministers would rather we never saw? Unless they publish the reports we can’t have any idea of what the state of play is.”

The MoD defended its decision to suppress the DNSR reports. “We no longer publish these reports during this age of intensifying threats as it would risk our national security,” said an MoD spokesperson.

“Our nuclear programme remains fully accountable to ministers, faces regular independent scrutiny and review, and continues to meet all the required standards.”

The Labour Party has not responded to a request to comment.

Nuclear safety risks identified in reports by the Defence Nuclear Safety Regulator

2014-15: five risks - shortage of engineers “the principal threat to the delivery of nuclear safety”

2013-14: eight risks - sustainability of the necessary nuclear skill set “remains fragile”

2012-13: eight risks - ageing nuclear submarines require attention “to ensure maintenance of adequate safety performance”

2011: eight risks - “lack of adequate resource to deliver the defence nuclear programmes safely”

2010: eight risks - danger of accidents “progressively worse” because of “painful” spending cutbacks

2009: nine risks - spending cuts meant that it was no longer possible to ensure that nuclear activities “remain safe”

2008: nine risks - some areas “barely resourced” to deliver nuclear safety

2007: 11 risks - "potentially significant risks" at nuclear sites across the UK

2006: 11 risks - “crew fatigue" could cause hazards during the road transport of nuclear weapons

2005: nine risks - “slow progress in implementing the regulation framework for the nuclear weapons programme”