What is the official designation of the building visible from the Morpeth Arms in a manner enabling spying?
SIS Building The SIS Building or MI6 Building at Vauxhall Cross houses the headquarters of the Secret Intelligence Service (SIS, MI6), the United Kingdom's foreign intelligence agency. It is located at 85 Albert Embankment in Vauxhall, a south western part of central London, on the bank of the River Thames beside Vauxhall Bridge. The building has been the headquarters of the SIS since 1994.
Air Observation Post Air Observation Post (AOP) is the term used by the Royal Air Force and other services of the United Kingdom and Commonwealth air forces, for an aeroplane or helicopter used in the role of artillery spotter. In this role, either the pilot of the aircraft or a passenger acts as an observer watching for targets on the ground, and/or as a Forward Observation Officer directing the fire, by radio, of artillery on the ground (or calling in tactical ground-attack aircraft).