The diplomatic pouch (also called the diplomatic bag) is one of the oldest and most jealously guarded instruments of diplomatic tradecraft. Its modern legal basis is Article 27 of the Vienna Convention on Diplomatic Relations (1961), which provides that the pouch shall not be opened or detained and that packages constituting the pouch must bear visible external marks of their character and may contain only diplomatic documents or articles intended for official use. A parallel protection for consular bags appears in Article 35 of the Vienna Convention on Consular Relations (1963), though consular bags may, in narrowly defined circumstances, be requested to be opened in the presence of authorities or returned to origin.
In practice, the pouch can range from a small wax-sealed envelope to entire shipping containers or aircraft pallets. It is typically accompanied by a diplomatic courier carrying an official document attesting to their status and the number of packages, though unaccompanied pouches entrusted to commercial carriers are also permitted.
The inviolability of the pouch has occasionally been tested. The 1984 Dikko affair, in which a former Nigerian minister was found drugged inside a crate at London's Stansted Airport labelled as diplomatic baggage, prompted debate because the crate was not properly marked and therefore did not qualify for protection under Article 27. Allegations of pouches being used to smuggle weapons, narcotics, currency, or intelligence material recur, but receiving states have very limited remedies short of declaring the courier persona non grata or returning the bag unopened.
The International Law Commission produced Draft Articles on the Status of the Diplomatic Courier and the Diplomatic Bag in 1989, but they were never adopted as a binding treaty, leaving the Vienna regime as the principal source of law.
Example
In 1984, UK customs officers at Stansted Airport opened a crate labelled as diplomatic baggage and discovered the abducted former Nigerian minister Umaru Dikko inside, ruling the crate was not a protected diplomatic pouch because it lacked the required external markings.