Sandy Denny was the most outstanding female singer that Britain has produced

She died, a burnt-out case, 40 years ago this week. She was 31 years old. The proximate cause of her death was a cerebral haemorrhage as a result of a fall downstairs. But her life had for a long time been a downward spiral of drink, drugs and loss of control.

Professionally it seemed to be all over. Her voice had gone (she had chain smoked for years); her weight had ballooned; her recording contract had not been renewed; her…