A rule embodies in a treaty is competent to exclude

- A rule embodies in a treaty is competent to exclude the operation of
any rule of customary international law
International Court of Justice identification of customary international
law
- states shall respect and enforce “the basic rights of human persons”
- states shall enjoy freedom of navigation
- states shall resolve their disputes peacefully
- states shall not intervene in the affairs of other states
- states shall not pollute the environment
- states shall enjoy the eight od self-defence against armed attacks by
other states
- states shall not acquire territory by war
- dualism does not apply to international custom

Peremptory norms
- Bind all sovereign with or without state practice or assent
e.g. prohibitions against slavery, torture, aggressive war
- Doctrine of universal jurisdiction
- Obligates all states to enforce peremptory norms domestically
- But China is skeptical towards the doctrine> HK is unlikely to
enforce peremptory norms
Chung Chi Cheung v R ]1939]
AC:
Treat customary law as
incorporated into domestic law
so far as it is not inconsistent
with rules enacted by statute
C v Director of Immigration
[2011] 5 HKC (CA) :
no litigant may assert rights
under a rule of customary
international law which has
been “clearly overridden by
domestic legislation to the.
Contrary”
Vienna Convention on the Law
of Treaties 1969
- Any existing treaty which
is in conflict with a new
peremptory norm become
void and terminates
- A treaty is void if at the
time of its conclusion, it
conflicts with a
peremptory norm of
general international law
Internationa
l Judicial
Decisions
- 120 international dispute settlement bodies

Assumed mantle of “courts” and “tribunals”

No comprehensive judicial hierarchy, not enforcing judgments of
international courts
International Court of Justice
Prosecutor v Tadic (1996)
International Criminal
Tribunal:
- Every tribunal is a self-
contained system

- Judicial organ of UN, informally known as World Court
- Most prestigious of all international tribunals, but has no formal
relationship to other tribunals
- Does not serve as a court of last resort
- Has jurisdiction only when state parties consent to it
- Not precedential, only binds parties to that case
- Rules and principles tend to be accepted by states as customary
international law
Examples of international courts
- WTO Appellate Body
- International Tribunal For the Law of the sea
- International Criminal Court
Regional:
European Court of Justice

Decisions of international courts are not binding, but provide
influential guidance and persuasive authority
- Domestic courts may assign varying degree of persuasiveness
- HK became a host country for the Hague-based Permanent Court of
Arbitration> host arbitrations involving states and companies, both
public and private, mostly from Asia, e.g. Republic of the
Philippines against ORC’s “nine-dotted” line claim over South
China Sea
- No integrated judicial
system operating in an
orderly DOL
Koon Wing Yee v Insider
Dealing Tribunal (2008) CFA:
- In respect of the
jurisprudence of European