A Royal Navy petty officer was jailed for eight years yesterday for trying to pass Britain's nuclear submarine secrets to men he believed to be Russian spies.
Edward Devenney, 30, who was based at Devonport and arrested in Plymouth, was told he had betrayed his country and his colleagues.
Mr Justice Saunders, sentencing him at the Old Bailey, said Devenney knew what he was doing when he met the two men in January.
He added: "He did supply details of movements and operations carried out and to be carried out by nuclear submarines.
"I am satisfied that in the wrong hands it was capable of affecting the operational effectiveness of nuclear submarines.
"This is a very serious case. The defendant was prepared to betray his country and his colleagues."
Devenney, who comes from Northern Ireland, had suffered as the result of a rape allegation of which he was later cleared.
But by January this year, when he met the men in London, Devenney was a "controlled and rational man", the court heard.
No damage had actually been done to national security because the Russians were in fact MI5 intelligence officers, but Devenney had not known that at the time.
The sailor pleaded guilty to breaching the Official Secrets Act by gathering classified information and misconduct by meeting the supposed spies.
Outside court, solicitor Richard Cannon read a statement on behalf of Devenney which said: "I am deeply sorry for the hurt and shame that I have brought on my family and loved ones.
"Prior to these events I gave the Royal Navy 11-and-a-half years of service and I deeply regret my actions and the effect they have had on the Submarine Service and colleagues."
Mari Reid, unit head for the CPS counter-terrorism division, said: "This was a classic story of betrayal.
"Edward Devenney was employed by the Royal Navy to protect this country from potential threats to our security. Instead, he pursued a course of conduct likely to put his country at risk.
"We rely on the men and women of our armed forces to keep us safe. It is hard to imagine a greater breach of that role than Devenney's actions."
The court heard that Devenney rang the Russian Embassy in November last year, after what he said was a 12-hour drinking binge.
He thought he had been treated badly by the Royal Navy because he was not promoted to chief petty officer.
Two days later, he managed to get into a locked safe on board HMS Vigilant and took three photographs of part of a secret code for encrypted information. The judge said: "The photographs could, with other information, have led to the breaking of the code."
Lord Carlile, for Devenney, read out a statement from him which said: "I would like to apologise for the shame I brought on the Royal Navy."