In the legal term, immunity generally means that the person is exempted from prosecution, in other words the law and its executors cannot prosecute the person. The Vienna Convention on Diplomatic Relations (1961) states that the immunities and privileges are not intended to benefit individuals; rather they are to perform the functions of diplomatic missions as representatives of states.
Therefore, granting immunity to diplomats is intended to ensure that they perform their duties, and it is not to benefit them personally. Immunity is given to them as the authority of the sending state.
On the other hand, among the behaviors of diplomats in the host country, two most prominent principles have been repeated in all diplomatic law instruments, namely the principle of non-interference and the principle of respect to the laws and regulations of the host country.
a. Non-interference principle
Non-interference in the domestic affairs of a state is one of the fundamental principles of international law and a reflection of autonomy and equality of states. No government allows interference in its domestic affairs without its own will.
Advocacy of political parties and groups, spreading opposition press, taking stance on election, participating in rallies, criticizing the host country’s domestic and foreign policy, and any action taken to disregard party autonomy is considered as interference.
The principle of non-interference by diplomats is a common and accepted practice. But since the domestic affairs of states have a significant and growing impact on foreign policy, this principle is ignored by deceit in the countless cases. Financial or economic aid is among these deceits.
Another point regarding the non-interference principle is that there is a narrow line between intervention and espionage. The issue is so complicated that the International Court of Justice in its 1980 stated in its verdict regarding the case of the U.S. embassy in Tehran that it is difficult to distinguish between espionage and interference in domestic affairs.
Observing the interests and security of the host state and maintaining its legal system is an inviolable principle, which is prior to the immunity of diplomats. According to the Canadian case law, "When diplomats' behavior endanger the security of the host state, their immunity will be significantly voided."
Party autonomy is the most fundamental principle of constitutional law of states, and if a state accepts restrictions on its autonomy by granting immunities, it will also comply with the fundamental elements of autonomy.
b. The principle of respect to the laws of the host country
Diplomats are sent to the receiving country to represent the sending country, protect their country’s interests and nationals, promote friendly relations and develop cultural, scientific and economic relations between two countries (Article 3, the 1961 Vienna Convention on Diplomatic Relations). Without prejudice to their privileges and immunities, it is the duty of all persons enjoying such privileges and immunities to respect the laws and regulations of the receiving State (Article 41).
Respect to the laws the receiving state is a rational requirement for granting immunities, based on which the security and interests of the receiving state are ensured.
Obviously, the abuse of immunity is not only in clear conflict with diplomatic objectives, but also may disrupt domestic and international order.
Considering these issues, we can discuss the arrest of the UK ambassador to Iran.
According to Iranian security officials, the U.K. ambassador was filming and inciting the demonstration in front of Amirkabir University in the evening of January 11.
To examine the legal aspects of this issue, it should first be noted that Clause 2 of Article 6 of the Political Parties Law states, “Organizing public demonstrations is permissible under the following conditions: the Interior Ministry has prior knowledge. No weapons are carried. The Article 10 Commission does not find the event incongruent with Islamic basics. Also, gatherings in public parks and squares are allowed as long as a permission is obtained from the Interior Ministry”.
So the British Ambassador's tweet, which stated that he only participated in a rally to pay tribute to the victims of the plane crash, is not convincing, as the gathering was unauthorized and it was not something that the ambassador could not find out.
The UK ambassador is well aware of Article 41 of the Vienna Convention on Political Relations regarding respecting the laws and regulations of the receiving state and not interfering in its domestic affairs.
However, Iranian authorities have released him in full compliance with international regulations and obligations, shortly after he was identified.
In fact, secretly presenting among protesters and not informing authorities led him to be arrested in first place, a matter which holds no responsibility for the Iranian officials.
Accordingly it is the British government and its ambassador to Iran that must be held accountable for explicitly violating international law and abusing its political position.