3. Illegality

Simple ultra vires

No power at all: A body that does something its statute does not authorise acts ultra vires. In Attorney-General v Fulham Corporation a council with power to provide wash-houses could not run a laundry service for the public.

Errors of law

Jurisdiction: In Anisminic v Foreign Compensation Commission the Commission misread the rules it had to apply. The House of Lords held that its decision was a nullity, despite a clause saying its determinations could not be called in question in any court. After Anisminic, an error of law that affects the decision will usually take the body outside its power.

Improper purpose

Using power for another end: A power given for one purpose must not be used for another. In Padfield v Minister of Agriculture the minister refused to refer a complaint to a committee because the result might embarrass him. The House of Lords held that he had used his discretion to frustrate the policy of the Act.

Relevant and irrelevant considerations

What must be weighed: The decision-maker must take into account what the statute requires and must ignore what is irrelevant. In R v Home Secretary, ex parte Venables the Home Secretary took account of public petitions demanding a longer sentence for two child offenders, and the decision was quashed.

Fettering discretion

Over-rigid policies: A body may adopt a policy, but must not apply it so rigidly that it refuses to consider an individual case. In British Oxygen v Minister of Technology the House of Lords accepted a policy, provided the minister was willing to listen to anyone with something new to say.

Unauthorised conditions: In McCarthy and Stone v Richmond LBC the council charged a fee for informal advice on planning applications. The House of Lords held it had no power to charge.

Ouster clauses

Narrow reading: Clauses that try to exclude the courts are read narrowly, as Anisminic shows. Clear words are needed to remove the courts' supervisory role.