F was a 36 year old woman with serious mental disability who had been a voluntary in-patient at a mental hospital since the age of 14. She had begun a sexual relationship with a male patient. Hospital staff considered that F would not be able to cope with pregnancy and child birth and, as other forms of contraception were unsuitable, it was in F’s best interests for her to be sterilised by undergoing a hysterectomy.

F’s mother, who agreed with the hospital’s view, sought a declaration from the High Court that such an operation would not be unlawful by reason of a lack of consent and/or an order that the Court would consent to the operation.

The HL upheld the declaration made by Scott Baker J subject to minor amendments. The HL held that:

• as the Court’s parens patriae jurisdiction in respect of mentally disordered adults had been revoked by the Mental Health Act 1959, the giving of medical treatment to such adults was governed by the common law save where the Mental Health Act 1983 applied
• at common law the Court had no jurisdiction to consent to medical treatment on behalf of such adults
• the Court could under its inherent jurisdiction make a declaration that the proposed treatment would be lawful. 
• Lord Goff rejected the idea that treatment might be lawful under the exception relating to physical contact which is generally acceptable in the ordinary conduct of everyday life: medical treatment had to be justified on another principle. Lord Goff identified the relevant principle as being that of necessity. For the defence to apply ‘not only (1) must there be a necessity to act when it is not practicable to communicate with the assisted person, but also (2) the action taken must be such as a reasonable person would in all the circumstances take, acting in the best interests of the assisted person’ (at 75).