Devenney was arrested in Plymouth back in March

A navy submariner who offered to hand over secrets to MI5 agents posing as Russian spies had been passed over for promotion, a court has heard.

Petty Officer Edward Devenney, 30, originally from County Tyrone, admitted breaching the Official Secrets Act by collecting classified coding material.

He gathered details of “crypto material” useful to the UK’s enemies.

He also admitted a charge of misconduct in a public office. He will be sentenced later.

The court has been told Devenney, who was arrested in Plymouth in March, had been passed over for promotion because of defence cuts and was on the verge of being fired.

Devenney, who lived in Barnstaple, Devon, was a communications engineer on nuclear sub HMS Vigilant when he rang the Russian Embassy in November 2011.

According to the Royal Navy website HMS Vigilant, one of four submarines, equipped with Trident nuclear missiles, was launched in 1995. She recently underwent a £300m upgrade and was in dock at Devonport at the time of the offence.

‘Betrayal’

Devenney also offered details of HMS Vigilant’s movements, including plans to sail to its base at Faslane on the Firth of Clyde and then to the United States for nuclear missile testing.

Mark Dennis QC, prosecuting, said his fellow submariners felt what he had done was a “betrayal of the secrecy, loyalty and trust”.

At the time of the offence Devenney was drinking heavily, suffered bouts of depression and had just been cleared of rape, the Old Bailey heard.

He asked for his training course for promotion to be deferred for a year but he was warned he faced the sack after prolonged absences without leave, the court heard.

The MI5 agents recorded meetings at various venues, including the British Museum, in which he said he was angry with the Navy and did not want payment for the crypto material – programmes used to encrypt secret data.

At one point he told one of them: “Your accent sounds remarkably fake and like British intelligence.”

Mr Dennis said: “The potential damage could have been considerable and could have harmed the safety and security of the United Kingdom.”

The BBC’s security correspondent Gordon Corera said the case had gone into a secret session to assess the potential harm to national security; sentencing is due around lunchtime on Wednesday.

Devenney was charged under the Official Secrets Act for collecting information for a purpose “prejudicial to the safety or interests of the state” between 18 November 2011 and 7 March 2012.

He contacted the Russian embassy on his girlfriend’s mobile phone in an attempt to pass on information on the operation of HMS Trafalgar and two other nuclear submarines.

Devenney denied a second charge under the Official Secrets Act of communicating information to another person. This will not be pursued by prosecutors as no secret information was passed on.

Mr Dennis said he had security clearance to go into a room where secret material was kept in a safe.

He was not authorised to open the safe but managed to take three pictures on his mobile phone which showed secret information which held “the essential piece of the jigsaw” to encrypted material, the court heard.

Devenney transferred the pictures to his laptop – hidden in a folder called The Falklands War – but was arrested before he could pass them on.

If the data had been handed over it might have enabled a foreign power to set up an operation to capture the unique acoustic signature of the submarine – meaning it would lose its ability to move secretly underwater, Mr Dennis said.

He said: “The threat posed by Devenney’s actions was simple. If he had passed on information of the movements of a sub, then a foreign power would have been able to track it and capture its acoustic signature – the sound wave it leaves in the ocean.

“Each sub has its own sound which is effectively like a fingerprint – hear it once and you can identify that sub forever – and that means the nuclear deterrent provided by hidden submarines would be completely compromised.”

Source – BBC