The department has not released details of the timepieces or issued photos but it is believed nine clocks were stolen from storage at the FCO’s King Charles Street building off Whitehall, in Westminster, during July 2019.
According to newspaper reports their value is £53,000.
An FCO spokesperson said: “We take security extremely seriously and we continually review our processes.”
The theft was initially investigated internally and then reported to the police last year but the Met Police said there was insufficient evidence to proceed further.
Without descriptions and images it is difficult to identify the missing clocks and the police said the investigation has been closed “pending further investigative opportunities”.