Di dalam kes Council of Civil Service Unions & Ors v. Minister of Civil Service [1985] AC 374 yang mana telah diguna pakai oleh Mahkamah Persekutuan dalam kes R Rama Chandran v. The Industrial Court of Malaysia & Anor [1997] 1 MLJ 145 seperti berikut: “In this context, it is useful to note how Lord Diplock (at pp 410– 411) defined the three grounds of review, to wit, (i) illegality, (ii) irrationality, and (iii) procedural impropriety. S/N vcmbaGXDgEWdztTxsESXw This is how he put it: By 'illegality' as a ground for Judicial Review I mean that the decision maker must understand directly the law that regulates his decision making power and must give effect to it. Whether he has or not is par excellence a justiciable question to be decided, in the event of a dispute, by those persons, the judges, by whom the judicial power of the state is exercisable. By 'irrationality' I mean what can by now be succinctly referred to as 'Wednesbury unreasonableness' (see Associated Provincial Picture Houses Ltd v. Wednesbury Corp [1948] 1 KB 223). It applies to a decision which is so outrageous in its defiance of logic or of accepted moral standards that no sensible person who had applied his mind to the question to be decided could have arrived at it. Whether a decision falls within this category is a question that judges by their training and experience should be well equipped to answer, or else there would be something badly wrong with our judicial system. To justify the courts' exercise of this role, resort I think is today no longer needed to Viscount Radcliffe's ingenious explanation in Edwards v. Bairstow [1956] AC 14, of irrationality as a ground for a court's reversal of a decision by ascribing it to an inferred though undefinable mistake of law by the decision maker. 'Irrationality' by now can stand on its own feet as an accepted ground on which a decision may be attacked by Judicial Review. I have described the third head as 'procedural impropriety' rather than failure to observe basic rules of natural justice or failing to act with procedural fairness towards the person who will be affected by the decision. This is because susceptibility to Judicial Review under this head covers also failure by an administrative tribunal to observe procedural rules that are expressly laid down in the legislative instrument by which its S/N vcmbaGXDgEWdztTxsESXw jurisdiction is conferred, even where such failure does not involve any denial of natural justice. Lord Diplock also mentioned 'proportionality' as a possible fourth ground of review which called for development.”