Wednesbury [1948]

Greene MR gave two meanings to reasonableness.
sense’ –
courts to intervene where decision was of type which could not be made at all –
therefore illegal.
used synonym for host of other more specific grounds of attack, eg acting for
improper purposes, acting male fide.
sense’ – Decision may be attacked if conclusion reached is ‘so unreasonable
that no reasonable authority could ever have come to it’.