States as international persons — Recognition — Of States — Colony — Southern Rhodesia — Unilateral declaration of independence — Status in law of England — Relevance of international recognition — Acts of judges appointed by usurping government — Whether valid and effective — Divorce decree granted to wife domiciled in Rhodesia by such a judge — Whether effective in English law — Doctrine of necessity — Doctrine of de facto status — Whether validating such judicial acts — The law of England.