Page 199
subject of international law, with rights and duties under it.
13
Perhaps the most important aspect of
separate international legal personality is that the international organisation can enter into treaties
with other subjects of international law, whether member states, non-member states or other
international organisations.
14
Its constituent treaty may provide that it shall have international legal
personality; otherwise, this may be inferred from its purpose, the powers given to it by its members
and its practice.
15
The constituent treaty will usually provide also that in the territory of each member the
organisation shall have the legal capacity it needs to carry out its functions, such as entering into
contracts, buying and selling land and taking part in legal proceedings. This means, in effect, that
each member must accord it the status of a corporation in its domestic law. Whether this requires
legislation will depend on the constitutional law and practice of the member. In the United
Kingdom, and possibly in some other states that follow the dualist approach to the status of treaties
in domestic law,
16
the fact that the United Kingdom is a party to a treaty establishing an
international organisation will, in itself, not accord it legal personality in United Kingdom law.
There will usually have to be legislation (either an Act of Parliament or an Order in Council under
the International Organisations Act 1968) to accord it corporate status.
17
When legal personality has
been conferred on an international organisation by the law of a member state, the law of a non-
member state may treat the organisation as having legal personality even in that state.
18
Immunities and privileges
To ensure that ministers, diplomats and other officials attending meetings of an international
organisation, whether at its headquarters or elsewhere, are free from interference in carrying out their
duties, they enjoy certain immunities and privileges. They are also accorded to the organisation itself
and its staff. The guiding principle is that there must be a functional need for immunity, primarily to
ensure independence of the participants and the organisation. Certain fiscal privileges are accorded
to
13. On subjects, see p. 13 above.
14. On treaties with international organisations, see p. 53 above.
15. Reparations for Injuries Suffered in the Service of the United Nations, ICJ Reports (1949), p. 174; 16
ILR 318. Because they were not established by treaty, there may be some doubt whether the
Commonwealth or the OSCE have international legal personality.
16. See p. 81 above.