Aliens — Deportation — National security — United Kingdom Immigration Act 1971, Section 15 — Absence of right of appeal against deportation order for reasons of national security — Lebanese national resident in United Kingdom for over 15 years — Outbreak of hostilities in the Gulf in 1991 — Alleged links of deportee with organizations liable to instigate terrorist attacks in the United Kingdom — Whether necessary that deportee be given specific reasons for deportation order — The law of England