P, a local authority, under statutory powers, raised rents which D, a tenant, refused to pay. D sought to counterclaim that the rent increase was Wednesbury unreasonable. P sought to have this defence/counterclaim struck out on the basis that claims as to public law rights should be made via judicial review. HL found for D, holding that it was a paramount principle that the private citizen's recourse to the courts for the determination of his rights was not to be excluded except by clear words and that there was nothing in the language of R.S.C., Ord. 53 which could be taken as abolishing a citizen's right to challenge the decision of a local authority in the course of defending an action of the present nature, nor did section 31 of the Supreme Court Act 1981 which referred only to an "application" for judicial review have the effect of limiting a defendant's rights. Where the issue of a private law right depending on a prior public law decision is raised as a defence to a claim, then the point does not have to be dealt with by judicial review.
Lord Fraser: “It would in my opinion be a very strange use of language to describe the respondent's behaviour in relation to this litigation as an abuse or misuse by him of the process of the court. He did not select the procedure to be adopted. He is merely seeking to defend proceedings brought against him by the appellants. In so doing he is seeking only to exercise the ordinary right of any individual to defend an action against him on the ground that he is not liable for the whole sum claimed by the plaintiff. Moreover he puts forward his defence as a matter of right, whereas in an application for judicial review, success would require an exercise of the court's discretion in his favour.”