A Royal Navy petty officer is due to be sentenced for trying to disclose secret movements of British nuclear submarines to Russian spies.
Submariner Edward Devenney, 30, pleaded guilty at the Old Bailey last month to breaching the Official Secrets Act.
Devenney, who had been living at HMS Drake in Devonport naval base in Plymouth also admitted misconduct in a public office.
Edward Devenney was apparently motivated by spite - he began plotting treachery after the promotion course he won a place on was scrapped due to cuts. When he met two MI5 officers posing as Russian spies, Devenney was apparently uninterested in the offer of money in exchange for information.
A Royal Navy spokesman said: "It would be inappropriate for the service to comment while legal proceedings are ongoing."
- Devenney admitted gathering details of "crypto material" - programmes used to encrypt secret information - which could be useful to an enemy.
- He was charged with collecting information for a purpose prejudicial to the safety or interests of the State between November 18 2011 and March 7 2012.
- The submariner admitted a charge of misconduct in a public office in relation to meeting two people whom he thought were from the Russian secret service and discussing information relating to the movement of nuclear submarines.
- He denied a second count of communicating information to another person and this will not be pursued by prosecutors.
Devenney, who was remanded in custody, will be sentenced on December 12 at the Old Bailey, when parts of the hearing will be held in secret.
Submariner Edward Devenney pleads guilty to collecting top secret Royal Navy codes and seeking a covert relationship with a foreign power.
Devenney offered details of an operation by HMS Trafalgar and sailing dates of two nuclear submarines to men he believed were Russian spies.
Devenney pleaded guilty at the Old Bailey to gathering details of encryption programmes in breach of the Official Secrets Act.
He also admitted a charge of misconduct in a public office in relation to a meeting with two people he thought were from the secret service of another state.
Royal Navy submariner Edward Devenney, 30, from Northern Ireland, has admitted collecting secret coding programmes that could be useful to an enemy of the UK and misconduct in a public office.