The Royal Navy's nuclear submarine force has shortages of trained specialists amounting to more than one in five of certain key sections of its Trident missile and hunter-killer boat crews.

Figures obtained by The Herald show that the four strategic and nine attack submarines have 28% shortfalls in senior nuclear engineering officers, a 23% deficit in sonar and sensor operators, and are 20% below requirement for strategic weapons systems' junior ranks. Communications experts and tactical warfare submariners, whose job is to operate conventional weaponry such as torpedoes, Tomahawk land-attack cruise missiles and anti-shipping mines, are in short supply to the tune of 13% and 24% respectively.

A Royal Navy spokeswoman admitted that there were recruitment and retention issues for the "silent service" but said the priority was nuclear safety. "The one thing we never compromise on is the safety of the reactors. Those compartments are always fully manned and maintained to the highest standards. That said, there are shortages at certain specialist pinch-points which we are now addressing.

"Submariners are a very special breed and submerged patrols for weeks at a time are not everyone's cup of tea. But there are shortfalls across the navy as a whole. We are trying to find ways to boost recruitment across the spectrum to ensure that we have a trained manpower pool to crew not only the future Astute attack boats, but also the two new carriers and Type 45 destroyers for the surface fleet."

The missile-carrying Vanguard-class Trident boats normally spend up to three months on patrol somewhere deep beneath the Atlantic, while the attack boats spend up to two months submerged.

All four Vanguard submarines and the last two surviving Swiftsure-class attack boats are based at Faslane on the Clyde. HMS Superb, the oldest attack submarine in the fleet, is limping 4000 miles back to the UK on the surface after damaging her main sonar on rocks in the Red Sea on Monday.

As reported exclusively by The Herald yesterday, the 32-year-old boat is likely to be decommissioned rather than repaired if the cost of replacing her is uneconomic.