A rule, administrative system or policy is unlawful if it gives rise to an “unacceptable risk of unfairness”. The threshold however is a high one. It requires showing unfairness which is “inherent in the system itself”, not just the possibility of aberrant decisions and unfairness in individual circumstances.
In MR v SoS (2021) EWCA Civ 541 it is held that, where there is systemic unfairness, it is not an answer to say that Judicial Review is available to correct unfairness in any single case. Nonetheless the important distinction must be maintained between adjudicating in cases, which is for the Courts, and determining policy, which is not.