Jump to Content Jump to Main Navigation
Diplomatic Law - Commentary on the Vienna Convention on Diplomatic Relations, 4th Edition by Denza, Eileen (14th January 2016)

Inviolability of Official Correspondence

From: Diplomatic Law: Commentary on the Vienna Convention on Diplomatic Relations (4th Edition)

Eileen Denza

From: Oxford Public International Law (http://opil.ouplaw.com). (c) Oxford University Press, 2015. All Rights Reserved. Subscriber: null; date: 10 December 2019

Diplomatic immunity — Diplomatic missions — Diplomatic relations

(p. 189) Inviolability of Official Correspondence

Article 27

  1. 2.  The official correspondence of the mission shall be inviolable. Official correspondence means all correspondence relating to the mission and its functions.

There was no clearly established rule of customary international law according inviolability to correspondence to or from a diplomatic mission which was sent through the public postal facilities. Letters to a mission would become archives or documents of the mission on delivery, but not before. Letters from a mission were not in practice sent through the ordinary post if they were of any importance or delicacy. It can be assumed that the authorities on occasion tampered with such letters, but such interference would usually be hard to detect and there do not appear to be instances where protest was made by a diplomatic mission.

The text of the first sentence of Article 27.2 was proposed in the International Law Commission by Mr Alfaro, who explained that: ‘The phrase “official correspondence of the mission” meant correspondence from the mission, that sent to the mission from its chancellery or other authorities of the sending State, and correspondence between the mission and consulates situated in the receiving State.’ The Rapporteur, however, accepted Mr Alfaro’s proposal ‘on the understanding that “official correspondence” applied only to mail emanating from the mission’.1 At the Vienna Conference the representative of Australia reintroduced as his own delegation’s amendment the definition of official correspondence now contained in the second sentence of Article 27.2.2 This addition does not help to clarify the question of whether only correspondence coming from the mission or also correspondence to it from the authorities of the sending State is to be given inviolability.

It is probable—although the point does not appear to have been settled—that ‘correspondence’ includes e-mails and their attachments which have become the most usual method of correspondence and can be regarded as essential for the performance of mission functions in the modern world. On this assumption there would be some degree of overlap between the protection accorded by paragraphs 1 and 2 of Article 27 as well as overlap between Articles 24 and 27.2.

The inviolability of official correspondence of a mission has two aspects—it makes it unlawful for the correspondence to be opened by the authorities of the receiving State and it precludes the correspondence being used as evidence in the courts of the receiving State. As regards use of correspondence as evidence, Article 27.2 may be regarded as duplicating the protection under Article 24 of the Convention which gives inviolability to the archives and documents of the mission ‘wherever they may be’. Correspondence from the sending (p. 190) government to its mission would also at least arguably be entitled to protection as archives of a foreign sovereign State.

The primary importance of Article 27.2 lies in the protection which it gives from interference by the authorities of the receiving State. In this context the second sentence is unhelpful, since it is not possible for these authorities to know whether correspondence relates to the mission and its functions without opening it and reading it—and with this the real damage has occurred. There is no obligation, as there is with the diplomatic bag, for mission correspondence to bear ‘visible external marks’ of identification. Correspondence to a mission at least indicates its destination, but it may not be clear whether it originates from the sending government and would thus be entitled to inviolability as archives of a foreign sovereign State. If the mission wishes to ensure that its outward correspondence is recognized as entitled to inviolability it should ensure that it is clearly marked on the outside.

In the nature of things there are likely to be few disputes over Article 27.2. A receiving State which wishes to intercept and read correspondence to or from a diplomatic mission will do so by methods which cannot be detected, including methods which do not involve opening it. Any complaints of wrongdoing will be rejected or blamed on mistake by a lowly official. Missions will continue to send confidential communications by cipher telegram or by sealed diplomatic bag, and will place little reliance on the uncertain protection given by Article 27.2 to correspondence passing through the public post.


1  ILC Yearbook 1958 vol I p 143.

2  UN Docs A/Conf. 20/C 1/L 154 (para 2) and A/Conf./20/14 p 179.