Extradition — Speciality — Accused liable to be extradited to Hong Kong — Reversion of Hong Kong to People’s Republic of China in 1997 — Whether violation of speciality principle in United Kingdom — United States Extradition Treaty — Double criminality — Requirement that conduct constitute an offence under laws of both the requesting and the requested State — Extent of requirement — Whether requirement satisfied by corresponding substantive elements of offence

State succession — Treaties — Extradition treaties — Hong Kong — Reversion of sovereignty to People’s Republic of China — Effect on United Kingdom — United States Extradition Treaty — Whether Treaty containing implied guarantee by Hong Kong that any person extradited there would not be prosecuted by a successor government — The law of the United States