The individual in international law — Nationality — Protected persons and de facto subjects — Protected persons expelled from State of residence — Whether Home State under duty to admit them — Whether obligation to admit expelled nationals applicable to mass expulsion — Ugandan Asians — Whether rule of international law conferring rights upon individuals — Effect of Immigration Act 1971 — Status of British protected person — Circumstances in which that status is lost — Whether need for express renunciation — Proof of nationality — The law of England