The case of a severely disabled man who wants the High Court to allow a doctor to be allowed to kill him would make the courts "legislatures rather than parliament", according to Baroness Finlay of Llandaff, a professor of palliative medicine at Cardiff University.

The law on assisted killing is "proportionate and clear" and has changed in line with medical progression in that if a patient refuses consent "there is still a duty of care" while they are dying.

She told the Today programme's Sarah Montague that a patient can refuse treatment by saying they do not want active care but they must still be looked after by care-givers.

She said that the "difficulty is setting a precedent" if this case is heard and is successful because protection in other cases may be removed.

In the case of Tony Nicklinson, Baroness Finlay disputed whether the only way to relieve his suffering is to kill him. She said that that the humane way is to look after someone and "negotiate with them every step of the way whether they want intervention".

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