The government is consulting on proposals for a legislative framework for substitute decision-

taking on behalf of mentally incapacitated people.

Advance directives on medical treatment - so-called living wills - have already been held to be effective by the courts, but legislation could further define their scope and efficacy, and give more certainty to patients and NHS trusts.

Legislation would also plug a large gap in the law. At present, no one can refuse or consent to treatment on behalf of someone else who lacks the capacity to do so.

The package, originally drawn up by the Law Commission, would allow people, while competent, to appoint friends or relatives as their attorneys to take such decisions if they lose capacity.

A court, possibly the Court of Protection, which now deals only with finance and property, would have power to take welfare and healthcare decisions as well, or to appoint a manager to do so.

The legislation would spell out which medical decisions could be taken by a healthcare attorney or court-appointed manager, which would need court approval and which would require a second opinion from an independent doctor.

Pending such legislation, the High Court's family division deals with a steady stream of treatment cases.

The latest, in November, was the first time the court was asked to declare that it would be lawful not to impose treatment on a patient where it was not 'reasonably practicable' to administer it.

A 49-year-old patient with a longstanding history of mental health problems and drug and alcohol abuse was judged to lack capacity to refuse or consent to treatment.

He had near end-stage renal failure and would soon need dialysis three or four hours a week for four hours at a time. Doctors believed he would be unable to co-operate with the treatment unless he was anaesthetised, which was impracticable.

An independent expert consulted by the Official Solicitor agreed and the court made the declaration.

Who Decides? Making Decisions on Behalf of Mentally Incapacitated Adults. Consultation paper issued by the Lord Chancellor's Department. Cm 3803, The Stationery Office, pounds12.70.