The £600m that is being spent on five offshore patrol vessels means that the Royal Navy must save an extra £500m over the next two months

The Royal Navy is scrambling to save an extra £500 million over the next two months after wasting money on ships it did not need because of a bungled procurement deal.

Contracts with BAE Systems for five offshore patrol vessels are the legacy of poor negotiations by the Ministry of Defence and mean that navy chiefs must find new savings to balance the books, defence sources said.

Options include cutting the size of the Royal Marines, mothballing one of two new aircraft carriers and even asking the army to pay for “soldier-like” jobs performed by marines, such as guarding naval sites.

A failure to meet the £500 million shortfall in the annual budget will mean that the army, Royal Air Force and Joint Forces Command,