“22. Judicial review conventionally is concerned with the question of jurisdiction and natural justice and the Court is not much concerned with the merits of the decision but how the decision was reached. In Council of Civil Service Unions Vs. Minister of State for Civil Service (1984) 3 All ER 935 the (GCHQ Case) the House of Lords rationalized the grounds of judicial review and ruled that the basis of judicial review could be highlighted under three principal heads, namely, illegality, procedural impropriety and irrationality. Illegality as a ground of judicial review means that the decision maker must understand correctly the law that regulates his decision making powers and must give effect to it. Grounds such as acting ultra vires, errors of law and/or fact, onerous conditions, improper purpose, relevant and irrelevant factors, acting in bad faith, fettering discretion, unauthorized delegation, failure to act etc., fall under the heading "illegality". Procedural impropriety may be due to the failure to comply with the mandatory procedures such as breach of natural justice, such as audi alteram partem, absence of bias, the duty to act fairly, legitimate expectations, failure to give reasons etc.