The claimants were 2 mental health patients, DJ and AN, who sought judicial review of the decisions of their respective mental health review tribunals not to discharge them from hospital. The key issue was whether the tribunals were mistaken in applying the civil standard of proof of a balance of probabilities when determining whether they satisfied the criteria for detention under sections 72 and 73 of the Mental Health Act 1983 (the Act). The claimants argued firstly, that the standard of proof that the detaining authority had to meet if seeking to prove the criteria for detention was the criminal standard of beyond reasonable doubt. Alternatively, they argued that the applicable standard was the “clear and convincing evidence” standard applied by the US Supreme Court in Addington v Texas; and finally, that the establishment of the criteria under sections 72 and 73 of the Act were susceptible to a standard of proof and the default position under both sections had to be, as a minimum, the ordinary civil standard of proof.
The High Court held that there was no support for the proposition that either the criminal standard of proof or some other standard of proof, which was indistinguishable from the criminal standard, had any application to anything that a tribunal was called upon to do. The application of such a standard would be impracticable having regard to the nature of the issues before the tribunal. According to Reid v SS for Scotland (1999) and R v MHRT, North & East London Region, SS for Health, ex parte H (2001) the applicable standard was the ordinary civil standard of proof. To raise the standard of proof above the ordinary civil standard of proof would be to undermine the purpose of the Act, which sought to protect the interests of the patient whose ability to act in his own best interest had been impaired, and to enable a proportionate balance to be struck between individual and public interests.
The standard to be applied under both section 72 and section 73 was the ordinary civil standard of proof as explained in Re H (minors) (Sexual Abuse: Standard of proof) (1996). Under both sections, with the exception of the question of whether the patient was suffering from a disorder under s.72 (1)(b)(i), the establishment of the remaining criteria did not involve a standard of proof but an exercise of judgment or evaluation. The fact that there was an onus or burden on the detaining authority did not necessarily carry with it some corresponding standard of proof and that proposition was contrary to authority. The fact that a statute required the court to be “satisfied” of something before it made an order did not mean that it had to be satisfied to the civil standard of proof. The default position under section 72 was that if the tribunal was not satisfied of the matters referred to in either s.72(1)(b)(i) or (ii), then it had to direct the discharge of the patient. In any other case, it might direct his discharge. Under section 73 the default position was that if the tribunal was not satisfied of any of the matters referred to in s.72(1)(b)(i) or (ii) or in s.73(1)(b), then it must direct the conditional discharge of the patient. In any other case, the tribunal would not direct discharge of the patient. The exception in s.72 (1)(b)(i) should be determined by reference to the civil standard of proof . The tribunal had to have regard to the particular dangers involved in relying upon hearsay evidence and had to bear in mind the need for proof to the civil standard in relation to past events which were important to the decision it had to take. It had to bear in mind the potential difficulties of relying upon hearsay, and if the incident was really fundamental to its decision, fairness might require that the patient be given the opportunity to cross-examine the witnesses if their evidence was to be relied on.