discuss the principle of judicial review
Judicial Review is the reassessment of the legality of actions or decisions made by those in position of public authority or bodies. The action or decision in question is brought before a Judge in court proceedings where the lawfulness of the decision is tested. The main purpose of Judicial Review is to ensure that public authorities do not act in excess of their powers and this explanation is supported in the following words of Sedley J “the purpose of Judicial Review is to ensure that government is conducted within the Law". 
It could be said that the subject matter of every Judicial Review is a decision made by a person in power, or, the failure of that person to make a decision. Nonetheless, it is important to note that in Judicial Review, it is always the legality of the decision that is explored by the courts. The decision itself does not necessarily have to be right or wrong. The court has to investigate as to whether there was lawful and fair action taken by the public body when reaching its decision.
Judicial Review is not a process of appeal and must only be used when all other avenues of resolution have failed. This must be recognised by any individual who seeks to apply for such review. The main variance between Judicial Review and appeal is that judicial review deals with the legality of the decision under the examination of the courts whereas the appeals process delves into the value of the decision under scrutiny.
It is known that an individual cannot apply for a Judicial Review if they do not have locus standi but where the case of David and Mary is concerned, the couple do have locus standi as both are suffering consequences as a direct result of the actions of the Local Housing Authority. It is for this reason that the couple have ‘sufficient interest’  in the matter and so would be entitled to apply for a review. It could be said that perhaps the courts have taken a somewhat restricted view of locus standi by holding that only those directly affected by an administrative action should have standing to apply for a review. However, in the case IRC v National Federation of Self-Employed and Small Businesses Ltd   when referring to those who should be able to apply for Judicial Review on the basis of locus standi, Lord Roskill stated it “impossible to find a phrase which was exhaustive or definitive of the class of person entitled to apply for judicial review".  Fundamentally, in his statement, Lord Roskill was backing the decision of the Rule Committee of the Supreme Court 1977 and the use of the phrase ‘sufficient interest’.  In the same case,  Lord Diplock stated that “It would be a grave lacuna in our system of public law if a single public spirited taxpayer, were prevented by outdated technical rules of locus standi from bringing the matter to the attention of the court to vindicate the rule of law and get the unlawful conduct stopped".  Basically, what Lord Diplock was saying here was that any public spirited individual should be allowed to challenge the legality of an administrative action. The Human Rights Act 1998  applies to public bodies and members of public authority and Section 6(1) says: "It is unlawful for a public authority to act in a way which is incompatible with a Convention right."  In accordance with this, section 7(1) states that “a person who claims that a public authority has acted (or proposes to act) in a way which is made unlawful by section 6(1) may—(a)bring proceedings against the authority under this Act in the appropriate court or tribunal, or(b)rely on the Convention right or rights concerned in any legal proceedings, but only if he is (or would be) a victim of the unlawful act".  This would allow the couple, David and Mary, relevant standing to bring the case forward for Judicial Review as they more than likely feel victimised by the Housing authority and the actions taken against them.
When illegality is used as a ground for Judicial Review, the individual or body making the decision must follow and undoubtedly comprehend the law that regulates their power and must give effect to it. If however, the power that the decision maker has is exceeded or acted outside of, then the actions would be considered to be ultra vires. We see an example of such powers being exceeded in Bromley Council v Greater London Council .  In this case, Bromley Council acted outside of the scope of their authority which had in fact been set down in legislation. The rising of taxpayer’s rates had been increased in this case to subsidise local public transport in London. However, the decision was reached on the basis of improper purpose, namely to reduce traffic congestion. In response to this, Lord Scarman stated “The unreasonableness of the decision i.e. that which would enable the Court to conclude that it is one which no reasonable authority could have reached, is that it proceeded upon a misconception of the duties imposed upon the appellants by the statute." 
In the case of David and Mary however, the Local Housing Authority felt that by moving the couple to a one bedroom house, they would be efficiently managing the level of local public housing. Regardless of this, it could be said that the couple felt that they were being treated unfairly due to David’s previous convictions, as mentioned by the local housing authority when reaching their decision to relocate the couple. Also the fact that the Local Housing Authority wants to move the couple to a less upmarket area can be seen as being unfair. The element of fairness demands that a public body must act fairly within its boundaries and should never act so unfairly that it amounts to an abuse in power.
On the other hand, the housing authority seems to have followed the procedures that had been laid down before them in The Public Housing Act 2010. They are acting well within their boundaries according to Section 1 of the act, as by re-housing David and Mary to a smaller property, they are ensuring that the supply of public housing is kept to a reasonable level. The Local Housing authority has also acted in accordance with Section 7, as the legislation outlined here grants them the power to force tenants to move to alternative housing when the house has 2 bedrooms or more yet is occupied by one person only and/or the Local Housing Authority in “its absolute discretion" believes that requiring an individual be re-located would ensure proper management of public housing.
In this case, the local housing authority is protected by the language used in the Public Housing Act 2010. The use of the words ‘power to force’ in section 1 of the act and also the use of the words ‘in its absolute discretion’ in section 7(2) covers the actions of the public authority. A literal approach to the legislation would be welcomed here in the defence of the housing authority. It has been heard in past cases that the courts have been advised not to steer clear of the literal interpretation of words used in a piece of legislation. We see evidence of this in R v Judge for City of London Court .  Here, Lord Escher asserts that “if the words of an Act are clear, then you must follow them, even if they lead to a manifest absurdity".  For these reasons it is not believed that the housing association have acted ultra vires.
However, had it not been the case that the words ‘power to force’ and ‘absolute discretion’ had not been used in the relevant legislation, then David and Mary would most certainly be able to bring the case for Judicial Review based on the grounds that the Local housing authority had acted illegally by discriminating against them. As illegality is considered to be the violation of the principles set down by public law, the local housing authority could be accused of refusing to take relevant information into account such as the couple not having any rent arrears and by the same measures, not ignoring irrelevant information either, such as the drug use and previous convictions of David. They could also have been seen to have fettered their discretion as a public authority by trying to apply rigid policies as if it were set out in legislation. For example, we see no mention of drug use, personal circumstances, prior convictions or even circumstances surrounding complaints from neighbours in the sections outlined in The Public Housing Act 2010. Yet, these were all factors that were discussed between the housing authority and the couple at the time the decision to re-locate them was being reached. We see an example of fettered discretion in BOC v Board of Trade   , where it was concluded that the Board had failed to implement its discretion in the correct manner. In this case, the board had applied a ‘blanket’ policy instead of taking individual applications on their intrinsic worth.
On the basis of the conclusions drawn in the above paragraphs, if, in the instance that this case did go to trial, I think that the courts would willingly accept that the couple have the locus standi to bring the case forward for Judicial Review based on the contents of sections 6 and 7 of the Human Rights Act . In the couples defence, the housing authority could be seen to have acted in bias of the couple, given the fact that they have mentioned drug use, David’s previous convictions and re-locating the couple to a less up market area. This is a vital rule in natural justice. The latin term Nemo judex in res sua translated means that no man should be a judge in his own case and this is a rule that is not taken lightly in the courts. For this reason, bias would probably be the best angle for the couple to come from in terms of attempting to win the case. The courts could refer to the case of Council of Civil Service Unions v Minister for the Civil Service   where Lord Diplock states that the decision made was “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".  If this test was applied in the case of David and Mary then the court would probably find that the housing authority had acted within their boundaries as stated in the legislation protecting their actions. Based on the findings laid out in the couples scenario, the court would probably not intervene or quash the decision as it could not be considered to be so demonstrably unreasonable as to constitute illegality.
In the unlikely event that the court does accept that the housing association has acted unlawfully, there is no guarantee of any remedies being granted. Granting remedies is at the absolute discretion of the courts. In order to receive remedy, David and Mary would have to have suffered substantial hardship or loss but as the local housing authority has offered them alternative housing, they have not suffered great hardship. If it had been the case where the housing authority had evicted the couple, leaving them homeless, the outcome of the case would be much different than what is predicted above. I feel that in bringing this case before the courts for judicial review, David and Mary’s attempt to triumph will not be successful as the local housing authority stayed within its boundaries as laid out in the legislation, i.e. The Public Housing Act 2010.