NUCLEAR submarines built in Barrow have parts regularly stripped out of them as the Royal Navy struggles to maintain its fleet.

A report has revealed the scale of Royal Navy vessels being "cannibalised" as the need grows to swap parts between ships and navy helicopters.

Nuclear-powered Astute-class hunter-killer submarines, one of the most modern and advanced vessels in the navy, experienced the highest level of cannibalisation in the fleet with 59 instances per boat on average.

Barrow and Furness MP John Woodcock laid blame at the government's door saying its "penny pinching" attitude caused delays to vital defence projects.

He said: "The Ministry of Defence is bearing down on Barrow shipyard workers over cost and schedules yet this report shows its own budget cuts and penny pinching are causing unnecessary delays to this vital programme.

"The cannibalisation problem could get even worse in the future with signs that the Tory government is battening down the hatches for Brexit and depriving the defence equipment programme of resources."

Equipment "cannibalisation" increased 49 per cent from 2012 to 2017 according to the spending watchdog the National Audit Office. It said budget cuts in the last two years could have increased the need to carry out the practice on navy vessels.

HMS Astute, the first of its class was launched in 2007 and at the time was the largest and most advanced nuclear submarine built for the Royal Navy.

The subsequent boats in the Astute class are some of the worst hit by cannibalisation. Some parts were taken from submarines as they were still being constructed - adding to delays in the production process - and costing the taxpayer millions of pounds.

In the past five years, the three in-service Astute-class submarines had 506 defects, with 28 per cent of the 313 resolved defects in 2016-17 fixed through cannibalisation. The remaining fixes were resolved by sourcing parts from the supply chain.

When defence secretary Michael Fallon cut steel on the then named "Successor" class of submarine - now named Dreadnought - he said that delays would be unacceptable and companies would be penalised for failing to meet construction targets.

However, Mr Woodcock said it was in fact the budget constraints put in place by government would be the determining factor in the delivery of the Dreadnought class.

He said: "The make-do, mend, and delay approach in the face of inadequate budgets only costs the taxpayer more in the long run and risks delaying the in-service date of strategically important vessels like the Astute-class and potentially Dreadnought."

Official guidelines surrounding the practice of 'cannibalisation' are fairly comprehensive. They say it should not take place when no other solution is available.

But, the NAO said delays in deliveries of spares and a lack of information about when parts will be available contributed to the increase in the practice. The NAO report noted that in some circumstances, such as during high-intensity operations, cannibalisation can be the most effective way to keep vessels at sea.

It noted: "The risk of cannibalisation has increased further with reductions in fleet sizes meaning the armed forces have limited alternative equipment to deploy."

A Royal Navy spokesman commenting on the revelations, said: "Less than 0.5 per cent of parts we use come from swapping components, and we only do this when it's absolutely necessary to get ships out of port and back on to operations more quickly.

"We continue to make improvements to how we manage this long-established practice."

The Mail has approached BAE System for comment on the NAO report.

Cannibalisation: What is it? Why does it happen? And what are the costs?

The National Audit Office report said the Ministry of Defence had taken decisions to cut support, which could have exacerbated the problem of cannibalisation.

"In the past two years, the Navy has removed an estimated £92m from its maritime support in-year budgets," the report said. That amounted to 34 per cent of the total £271m of maritime support budget cuts.

An estimated £22m of parts from submarines in production have been supplied to in-service parts and the practice delayed the completion of HMS Artful by six weeks, leading to an extra £4.9m in indirect costs.

The NAO said the Ministry of Defence had identified that cannibalisation has affected submarines currently in production "leading to an estimated £40m cost increase".

In the last five years, between 0.3 per cent and 1.4 per cent of parts provided to the main classes of ships and submarines have been cannibalised.

Between April 2012 and March 2017 there were 3,230 instances involving 6,378 parts, with 795 instances in 2016-17 alone - the equivalent of 66 a month, up from 30 a month in 2005. Cannibalisation can be functional but can actually increase costs.

In 50 per cent of cases on Type 23 frigates the expense of moving equipment was equal to or greater than the value of the part - and risks causing damage or disruption. An average 1.4 per cent of parts issued to Astute-class submarines involved cannibalisation compared with 0.4 per cent across all ships and submarines.

In the past two years, the Navy has removed an estimated £92m from its maritime support in-year budgets.