Britain’s domestic intelligence agency, MI5, conducted a covert 20-year operation to investigate suspicions that a senior MI6 officer was secretly working as a Russian spy, according to newly uncovered details of the high-risk mission known as Operation Wedlock.
The investigation, sparked by a tip-off from the CIA in the late 1990s, focused on a high-ranking member of the UK’s foreign intelligence service (MI6), amid fears they had been “turned by Moscow.” MI5’s inquiry was triggered when US intelligence became convinced that the officer was leaking classified information to Russian intelligence services.
Although MI5 deployed up to 35 surveillance and desk officers to track the suspected mole—dubbed “Suspect 1A”—the agency ultimately failed to obtain conclusive proof. Some intelligence officials believe the spy may have escaped detection, while others fear there could still be an undiscovered Russian agent within MI6.
MI5 surveillance spanned continents and decades
Operation Wedlock involved unprecedented inter-agency surveillance, with MI5 essentially spying on its sister agency. Officers tracked the MI6 suspect across Europe, Asia, and the Middle East—at times operating illegally under false names and using real passports. One team even stayed at a CIA safe house in the Middle East without the host country’s knowledge, a move that violated international law.
The surveillance team was stationed at a covert base in Wandsworth, south London, posing as a security company near MI6’s headquarters in Vauxhall. Their efforts included breaking into the suspect’s home to install listening and video devices, and using hidden cameras inside everyday items like tissue boxes.
Extreme secrecy and internal tensions
Due to the sensitivity of the case, team members were initially misled, being told they were on a training exercise. The operation’s lead officer was briefed in a church, and planning took place outside official MI5 premises to avoid leaks. Some within British intelligence likened the case to that of Kim Philby, the infamous MI6 officer who spied for the Soviet Union.
The officer under surveillance had access to highly sensitive intelligence, making the investigation especially urgent. While concerning behavior was observed during the surveillance, it was reportedly unrelated to espionage.
Did the mole escape—or remain undetected?
Sources say the suspect may have been aware of the surveillance, and there are fears he did not act alone. Two additional individuals based in London were believed to be involved. Despite the extensive resources allocated, MI5 never secured definitive evidence.
A source familiar with the case said: “It was the most serious and expensive internal operation MI5 has ever undertaken. If the wrong man was followed, it means MI6 may still have a mole.”
UK government sources have declined to comment on the matter.
