A PROJECT to build the next generation of Trident submarines is due to cost nearly £1.7 billion more than first anticipated, according to a report.

A plan released by the Ministry of Defence said the Dreadnought programme, involving four boats built in Barrow, will cost £1.69 billion more to finish than it was first thought when the plan was approved.

Details of the programme's cost changes were revealed in the Ministry of Defence's equipment plan for 2023.

A £31 billion budget with a further £10 billion contingency was set for the Dreadnought programme after it was approved by parliament.

The Ministry of Defence plan reported on the current projected costs of the departments projects.

It said around £10 billion had been added to the total bill due to inflation and around £2 billion from foreign exchange rates.

Analysing the plan, the National Audit Office (NAO) said the MoD's ten-year programme until 2033 was unaffordable and the projected deficit the biggest since 2012, when the plan was first published.

It puts the estimated costs at £305.5 billion against a budget of £288.6 billion.

Last's year ten-year estimate was under budget by £2.6bn.

The MoD said the report was based on a 'dated snapshot' from April.

A spokesman said while the report recognises the impact which rising costs and inflation are having on defence, it does not accurately reflect the current or future state of the armed forces equipment plan.

He added: “Our armed forces are operating in a world of increasing conflict, and this Government is working to deliver what our service men and women need to keep Britain safe.”

"Whilst this report recognises the significant impact global headwinds and high inflation has had on UK defence, it does not and could not accurately reflect the current or future state of the armed forces equipment plan," said a spokesman.

He said spending was increasing significantly and that 'decades long underinvestment' in certain areas was being rectified.

"The defence secretary is currently leading work to ensure the armed forces have the next generation equipment they need to defend Britain and maintain a strategic advantage," he added.