UK Government plans for the next generation of Trident submarine reactors are under threat from staff shortages and spending cuts, according to an expert report for the Ministry of Defence.

The report criticises the MoD’s nuclear submarine programme as “introspective”, “somewhat incestuous” and warns it’s facing a “perfect storm” of problems. It also urges the MoD to work more closely with the civil nuclear power industry.

Critics warn that the MoD is putting public safety at risk by cutting corners, and that nuclear defence could be “cross-subsidised” by the civil industry.

Last week former military chiefs warned that British armed forces were no longer fit for purpose. The army was 20 years out of date, the navy under-funded and the air force at the edge of its engineering capacity, according to General Sir Richard Barrons, who retired last year as commander of joint forces command.

The submarine report was commissioned by the MoD in 2014 after a radiation leak at the Vulcan reactor testing facility near Dounreay in Caithness. The leak forced a £270 million rejig of the refuelling programme for existing Trident submarines based on the Clyde.

But the report has been kept secret since then, until a heavily-censored version was released by the MoD earlier this month under freedom of information law.

It was written by three academics close to the nuclear industry – Professor Robin Grimes from Imperial College in London, Professor Dame Sue Ion who used to be a director of British Nuclear Fuels Limited, and Professor Andrew Sherry from the University of Manchester.

They were asked to review plans for a new reactor to power the Dreadnought submarines due to replace the four existing Trident-armed Vanguard submarines in the 2030s. The availability of specialist nuclear staff “appears to be at the bare minimum necessary to deliver the programme”, their report concluded.

“We believe the naval nuclear propulsion programme could soon be facing a perfect storm with an ageing expert community facing competition from a resurgent civil nuclear industry.”

Capability is “sparse”, they warned. They criticised the programme for a “culture of optimism” that assumed success. Research groups were “introspective and closed”, and the programme was viewed as “somewhat incestuous”.

They said that driving down cost was “potentially introducing consequent risks which do not to us appear to have been properly addressed.”

The MoD should, they said, “seek imaginative methods to better engage with the emergent civil new build programme on nuclear matters to the benefit of defence.”

The SNP insisted safety had to be paramount. “It is absolutely clear from this report, and many others we have seen, that the MoD is dangerously trying to cut corners – and that is clearly very worrying,” said the party’s defence spokesperson at Westminster, Stewart McDonald MP.

“I don’t know which is the more alarming, the amount of this report that is redacted or what we actually can read about the continued pressure to find savings in nuclear programmes.”

Dr Phil Johnstone, a nuclear researcher at the University of Sussex, said: “This report reveals that the difficulties experienced by the UK submarine programme are even more serious than was known before.”

There was great pressure “to engineer a cross-subsidy from electricity consumers to cover the huge costs of maintaining the military nuclear industry,” he argued.

His colleague at Sussex University, professor Andy Stirling, added: “Military pressures for secretive support to an uneconomic civil nuclear power industry are not just placing a burden on UK electricity consumers, but are threatening the rigour of public accounting and the accountability of UK democracy.”

Nuclear Information Service, the research group that obtained the report, pointed out that the public were already paying for submarine reactor mishaps. “Plans for the new Dreadnought submarines are based on the assumption that nothing will go wrong,” he said.“This cavalier attitude virtually guarantees that taxpayers will be picking up the bill for the MoD's complacency for decades to come.”

An MoD spokesman said, “The MoD ,of course, faces challenges in this highly-specialised area, which we work to meet,” said a spokesman.

“Our spending is carefully managed so we can rightly focus our rising budget on our priorities to keep the country safe whilst delivering value for money for the taxpayer. Our nuclear programme is fully accountable to ministers and faces regular independent scrutiny.”

He stressed that the MoD’s nuclear programme “absolutely” meets required safety standards. “This has not and will not be compromised and remains our priority,” he said.

None of the three authors of the MoD report responded to requests to comment.