DIPPRIV2300 - Diplomatic bags: inviolability
Diplomatic bags should only contain diplomatic documents or goods for the official use of the Mission and must conform to the regulations for prohibitions and restrictions.
Where a strong reason exists to suspect any misuse of a diplomatic bag, the FCO should be contacted in the first instance for advice on how to proceed. In cases where misuse is proven the bag should be returned BUT only with prior permission from the FCO or the relevant mission (a representative from the mission must be present).
The inviolability of a diplomatic bag should only be broken in order to save human life.