"She was severely diabetic so she took an overdose of insulin. She knew exactly what she was doing."
He said one of the causes of Miss Scharf 's crippling shyness was her overbearing father Freddie. Peppi met him in London when she was on holiday from her native Prague in 1937.
They fell in love and when, by the following year, it became clear that central Europe was not safe for Jews, she married Freddie by proxy, which enabled her to flee Czechoslovakia.
Almost all her family was later to perish in concentration camps, including Auschwitz. The couple started married life in London, where
Dorothy was born, but then emigrated to Australia, where Mr Scharf was the agent for wireless firm Grundig.
Mother and daughter returned to London following Freddie's death in 1970. Mr Barber said: "Dorothy began by collecting Old Master drawings but at a fairly early age switched to watercolours and especially Turner, with whom she was completely besotted.
"She had 13 Turners and it is not just the Courtauld Institute which is benefiting from her bequests - she also left paintings to the National Library and University in New South Wales as well as a museum in Israel.
"Unfortunately, she inherited her father's looks and he rammed it into her that no one would ever marry her. She had no confidence in herself. She was a typical poor little rich girl. She was frightened and shy and would only trust a limited number of people by the end of her life. It's very, very sad."
As well as collecting art, Peppi Scharf was an accomplished painter. She enjoyed having neighbours to tea but by contrast her daughter was so reclusive she would even hide from the cleaner.
Miss Scharf's private collection has been described as one of the most significant to be donated to the nation.
It includes eight Turners and works by Gainsborough, Cozens and Constable from the period 1750 to 1850, considered a golden age for British watercolour painting.
