The High Court has found that a Mental Health Tribunal failed to give adequate reasons for continuing the involuntary detention of a woman diagnosed with anorexia nervosa.
In a judgment delivered on 5 December 2025, Ms Justice Siobhán Phelan held that the tribunal's decision of 30 July 2024 did not demonstrate that it had properly applied the legal test required to detain the woman, identified only as KW.
KW had been involuntarily admitted to an approved centre in July 2024 after significant weight loss, restricted food intake and concerns that her condition had become life-threatening. Her weight was recorded at 36kg with a BMI of 14. A separate High Court order later authorised medical treatment, including nasogastric feeding.
The Mental Health Tribunal affirmed her admission under section 3(1)(a) of the Mental Health Act 2001. That provision requires a serious likelihood that, because of mental illness, a person will cause immediate and serious harm to themselves or others.
The tribunal recorded that KW remained extremely unwell, that the risks if she were discharged were serious and that inpatient treatment would benefit her condition.
However, the High Court found that this reasoning mixed the statutory test for immediate and serious harm with a separate test concerning the need for and likely benefit of treatment. Crucially, it did not explain why the risk of serious harm was also immediate at the time of the tribunal hearing.
Ms Justice Phelan stressed that the ruling did not mean detention under section 3(1)(a) could not have been justified. She found that the evidence before the tribunal could potentially have supported such a decision, including risks associated with refusal to eat.
The defect was the failure to explain how that evidence satisfied every part of the statutory test. The court found that this failure invalidated the tribunal's decision and said it would hear the parties on the form of the final order and consequential matters.