MI5 carried out Operation Wedlock, a major global investigation to identify a suspected spy, involving a team of 35 officers.

The search for a suspected spy, known as Operation Wedlock, was led by MI5, the British security agency. It mobilized a team of up to 35 officers who traveled around the world, including to the Middle East, where they stayed in a CIA safe house. The investigation, which spanned 20 years, failed to confirm whether MI6 had been infiltrated, raising suspicions that an agent may have been spying for Russia without being discovered.