Data received from monitoring at His Majesty’s Naval Base Clyde, popularly known as Faslane, suggest that the two submarines each went out on patrol for 157 days, one from January to June and the other from May to November, according to the report.
The Ferret cited Rob Forsyth, who commanded Royal Navy's nuclear submarines in the 1970s, as saying that such prolonged sea patrols could cause "operating errors", "a breakdown in morale" and pose a "threat to nuclear weapon safety."
In addition, sexual harassment and drug misuse are among the possible consequences of long voyages, according to Forsyth.
In accordance with the UK government policy, one of the country's four Vanguard-class submarines, which usually carry Trident nuclear warheads, should always be at sea for security reasons, the report said.