THE UK Government’s £43 billion plans to replace the Trident nuclear weapons system and build a new fleet of nuclear-powered submarines for the Clyde are “in doubt” or “unachievable”, according to a high-powered Westminster spending watchdog.

A new report from the Infrastructure and Projects Authority (IPA) to the Cabinet Office and the Treasury in London has condemned three major nuclear projects run by the Ministry of Defence (MoD) for being poorly managed, over-budget and beset by technical problems.

The financial rating for a submarine reactor manufacturing plant has been sharply downgraded for 2017, while two other nuclear submarine projects have had “major risks” every year for the last three years. All of the IPA’s assessment of a fourth £20bn plan to upgrade Trident warheads has been kept secret for national security reasons.

To try and combat the problems the MoD has launched a major reorganisation and set up a new Submarine Delivery Agency. It has also renamed the Trident replacement programme Dreadnought, and engaged in “rebaselining” to delay project delivery.

The IPA report, which covers 143 projects run by 17 UK Government departments, was posted online last week. Buried in a table and spreadsheet released at the same time were damning indictments of the MoD’s flagship nuclear projects.

A £1.7bn project to build new submarine reactor manufacturing plants at Rolls Royce in Derby called Core Production Capability is given the IPA’s worst rating of 'red' for 2017. “Successful delivery of the project appears to be unachievable,” said IPA.

“There are major issues with project definition, schedule, budget, quality and/or benefits delivery, which at this stage do not appear to be manageable or resolvable. The project may need re-scoping and/or its overall viability reassessed.”

The reactor plants were £250 million over budget and needed “rebaselining” to meet target dates, IPA said. It had previously rated the plants as “amber” in 2015 and 2016, meaning they they had “significant issues” requiring management attention.

The £31.6bn project to build four new nuclear-armed Dreadnought submarines to replace Trident and a £9.9bn programme to build seven new conventionally-armed nuclear-powered Astute-class submarines were both rated as “amber/red” for the third year running. All the submarines are due to be based at Faslane on the Gareloch near Helensburgh.

According to the IPA an amber/red rating suggests the schemes may not be viable. “Successful delivery of the project is in doubt, with major risks or issues apparent in a number of key areas,” it said.

“Urgent action is needed to address these problems and/or assess whether resolution is feasible.”

Three of the Astute submarines have been delivered to the MoD, and four are still to be completed. “Overall affordability remains the programme’s key challenge,” said the IPA.

The date when the nuclear-armed Dreadnought submarines are currently scheduled to be ready to replace ageing Trident boats has been kept secret. The Vanguard-class submarines that carry Trident nuclear missiles have already had their lives extended from 25 to 38 years.

The IPA has also assessed the financial viability of the MoD’s £20bn Nuclear Warhead Capability Sustainment Programme to upgrade the weapons. But its verdict has been deleted from its report on the grounds that it is exempt from freedom of information law under national security and defence provisions.

The Scottish National Party argued that Trident costs were escalating out of control. “A billion here – a billion there – to add to the bill for these weapons of mass destruction,” said SNP defence spokesperson, Stewart McDonald MP.

“The Westminster obsession with Trident is already squeezing conventional defence expenditure as everything else is sacrificed for these redundant, eye-wateringly expensive weapons. The Tories need to get a grip on costs if they insist on Trident renewal.”

Arthur West, chair of the Scottish Campaign for Nuclear Disarmament, pointed out that MoD projects kept going substantially over budget. “The Trident programme in particular continues to be a shambles from a cost point of view,” he said.

The Nuclear Information Service, which monitors nuclear activities, warned that the UK was going to encounter more problems building a new generation of nuclear weapons. “The delays and cost increases that we are already seeing cast further doubt on the MoD's ability to deliver these projects on time and within budget,” said the group’s research manager, David Cullen.

The MoD has set aside a “contingency” of £10bn in case replacing the four Trident submarines costs more that the estimated £31bn. There were matters relating to nuclear weapons that it could not discuss openly, it said.

“These ratings reflect the complexity and scale of delivering the most advanced submarines ever commissioned by the Royal Navy, the ultimate guarantee of our national security,” stated an MoD spokesperson.

“We are determined to get our submarine programmes right. That’s why we have established a new Director General Nuclear sponsor organisation and a new Submarine Delivery Agency.”