ON WHAT GROUNDS CAN JUDICIAL REVIEW BE SOUGHT?
The grounds for JR can be classified in at least three ways:
1. Two principal classes of action may be pursued under JR: those which allege that there has been a breach of statutory requirements, and those alleging that action has been taken in disregard of the rules of ‘natural justice’.
2. In Council for the Civil Service Unions v Minister of State for the Civil Service  AC 374 (the GCHQ case) Lord Diplock offered a threefold classification of the grounds for judicial review: (i) illegality; (ii) irrationality; and (iii) procedural impropriety. This is the classification followed below but it was accepted by the court that these categories were not exhaustive and might be added to in time. The classification is by no means perfect since the categories often overlap.
3.‘Illegality’ and ‘irrationality’ are often referred to jointly under the heading unreasonableness’ or ‘Wednesbury unreasonableness’ from the case with the same name.
Below we lay out the minimum of information you will need to know regarding each of these grounds for JR.
Relevant here is the doctrine of ultra vires, Latin for ‘acting outside one’s lawful powers’, or ‘in excess of one’s lawful powers’. It contrasts with action within one’s powers (intra vires). Bear in mind, however, that some of the cases, which are classified below under ‘illegality’, are referred to as ‘unreasonable’ or ‘Wednesbury unreasonable’ in parts of the relevant literature. There are several grounds for the courts to rule illegality or unreasonableness, as shown below.
Lack of authority
In its least problematic version the doctrine of ultra vires covers the ‘illegality’ of actions/decisions taken by public bodies that had no statutory authority to act/decide. For example, in R v Richmond upon Thames City Council ex parte McCarthy and Stone Ltd  AC 48 -
It was illegal for the local planning authority to levy a fee of £25 for informal consultation between corporation officers and property developers: charges can be levied on the public only on the basis of statutory authority and making charges was not an ‘incidental’ aspect of the normal functions of the planning authority.
Any administrative interference with the rights enshrined in the Human Rights Act 1988 (HRA) must be compatible/proportional. Under s.6 of the HRA, all public authorities are obliged to act/decide in a manner compatible with that Act, in other words either with full respect to the fundamental human rights it enshrines or by relying on legitimate reasons for interfering with such human rights (and only to the necessary degree). All public bodies, including courts and tribunals, are subject to the requirements of the HRA. Within JR the legality or illegality of any administrative decision/action’s interference with human rights will be determined by employing the principle of proportionality - a principle of Continental European jurisprudence which is now considered part of English law, at least with regard to human rights cases.
The principle of proportionality commands that power must be exercised only by means that are proportional to the objective that is being pursued. Thus, in
R v Chief Constable of Sussex ex parte International Trader’s Ferry Ltd  2 AC 418
The court assessed the proportionality of the decision of a Chief Constable to restrict the number of police officers present at a scene of confrontation between live animal exporters and animal rights activists: the number of police present had to be proportionate to the right of the exporters to export and of the demonstrators to engage in peaceful demonstration.
There is discussion as to whether the proportionality test constitutes a new heading of JR. In this regard, in