“The Borey-class strategic missile submarines can carry out the tasks of multi-role attack submarines by carrying other weapons on board – torpedoes and rocket-torpedoes. Just like a doctor of science can also teach math in a high school,” the source said.

The lead boat of the class, Yury Dolgoruky, was accepted into service by the navy at the end of 2012.

But Defense Minister Sergei Shoigu on September 6 ordered a delay in the acceptance of other such vessels into service and insisted on a further five firings of their principal weapon, the Bulava submarine-launched ballistic missile, following the failed test-firing.

The two newest Borey-class boats are complete and were due to be handed over to the navy by the end of this year.

A decision could be taken to use the boats in alternative roles as the Alexander Nevsky is ready and has shown no faults, the source said.

The navy’s Lada-class diesel-electric submarine St. Petersburg was similarly accepted for testing and trials in 2010 but is still not in operational service with the fleet, he said.