Aliens — Refugees — Criteria for grant of asylum — Refusal on ground of involvement in “serious non-political crimes” — Applicant claiming that threat to life or freedom because of political opinions if returned to Algeria — Applicant a member of illegal organization carrying out acts of violence to promote political objectives in Algeria — Admission by applicant of involvement in incidents leading to deaths — Whether requirement that gravity of offences be weighed against threat to life and freedom of applicant — Political nature of crimes — Whether nature of offence disproportionate to political objective — Requirement of causal link between offence and political aim — Convention relating to the Status of Refugees, 1951, Sections 1F and 33 — The law of England