The concession came from Nigel Giffin, QC, appearing at the High Court in London for the National Institute for Health and Clinical Excellence (Nice), which last year restricted NHS prescribing of the £2.50-a-day drugs to patients with moderate symptoms. This ruled out patients at the early and later, severe, stages of the disease. Nice decided the drugs were not cost effective in relation to the benefits they offered to sufferers in the early stages of the disease, and their carers - a decision later followed by the Scottish regulator, NHS QIS.

Under close questioning by Mrs Justice Dobbs, Mr Giffin said there were circumstances in which doctors, provided they took into account the Nice guidance, could exercise their own clinical judgment and decide that an individual patient was entitled to the drugs. NHS QIS said it would be closely watching the outcome of the case and Nice's response before deciding on its own course of action.

If Nice derestricts the drug, the patient charity Alzheimer Scotland expects NHS QIS to do likewise.