The Faslane naval base in Scotland, a British nuclear submarine base [AFP Yonhap News]

The captain of a British navy nuclear submarine has stepped down from his post following allegations of an inappropriate relationship with the wife of a man arrested on suspicion of spying for China, the Daily Financial Times (FT) and The Times reported on the 1st (local time).

According to sources, the British Navy launched an investigation last year into whether there was a "potential blackmail risk" after allegations surfaced that the married captain had an inappropriate relationship with Johnny Reid, a Member of Parliament from the ruling Labour Party.

Subsequently, when David Taylor, a former Labour advisor and husband of MP Reid, was arrested earlier last month on suspicion of assisting China's foreign intelligence agency, the Ministry of Defence conducted further security checks and concluded that there were no security breaches.

While the Navy deemed that the officer had not violated any regulations and did not impose disciplinary action, a source stated that measures were taken to mitigate potential risks after it was revealed that the officer and MP Reid had exchanged messages described as "flirtatious."

It is reported that MP Reid and the officer had known each other since their youth.

The officer stepped down from his post for personal reasons after the FT contacted the Ministry of Defence for comment. He has not resigned from the service.

Reid's husband, Taylor, has been released on bail in the Chinese espionage case and denies all charges. At the time, MP Reid stated that she had not noticed anything suspicious from her husband and that she and her children had no involvement in the case.

Her constituency is located about 50 kilometers from the Faslane naval base in Scotland, the core base of Britain's nuclear deterrent.

The Times also reported that MP Reid visited the base last year as part of the Armed Forces Parliamentary Scheme (AFPS), a military training program for parliamentarians, and allegedly engaged in inappropriate behavior with another senior officer in the officers' mess while intoxicated.

As a result, MP Reid withdrew from the program prematurely. Another MP who was present at the time reported the incident to Parliament recently after MP Reid's husband was arrested on espionage charges.

A Navy spokesperson said, "The security of our nuclear deterrent is our highest priority, and we have robust procedures in place to maintain the security of our personnel and capabilities," adding that they do not comment on individual cases. A spokesperson for MP Reid declined to comment, but her associates dismissed suggestions of any relationship with the officer in question and denied that the messages in question were flirtatious.