Relationship of international law and municipal law — Treaties — Application by municipal courts — Convention on the Transfer of Sentenced Persons, 1983 — Transfer of prisoner to serve sentence in State of nationality — Sentence imposed by foreign court — English court not able to impose sentence of such gravity — Scope of Secretary of State's discretion to vary sentence — Convention as aid to interpretation of municipal statute

Treaties — Interpretation — Convention on the Transfer of Sentenced Persons, 1983 — Travaux préparatoires — Vienna Convention on the Law of Treaties, 1969 — Sentence imposed by sentencing State differing from sentences under laws of administering State — Extent of discretion vested to vary sentence to comply with laws of administering State — Criteria of “similar offence” — The law of England