The father-of-two inherited more than pounds 15m from a cousin 10 years ago. But Mr Leech told friends he was too old to enjoy it and stayed in his modest semi-detached house in Minehead, Somerset, and began making anonymous donations to charity.
He gave pounds 100,000 to Minehead Football Club and made a large donation to the appeal for the families of the 16 people killed by the gunman Michael Ryan in Hungerford, near Mr Leech's hometown, in 1987. Schools, the disabled, and victims of the Armenian earthquake also benefited.
He died from burns at a seafront residential home when he dropped a lighted match in his lap and tried to douse it with a glass of brandy.
Jim Parsons, his friend and executor, said: 'He was completely unpretentious. He just wanted a quiet life. After he received his inheritance he didn't buy anything new, he just lived the same way.
'He always gave anonymously to charity. He didn't want any fuss. I think he would be a bit cross if he found out that he had finally been discovered as a great benefactor. Just about everyone has benefited from his acts of kindness, without the slightest clue who was behind them. He always made sure that others shared in his good fortune.'
Mr Leech left about pounds 1m to family and friends. Other beneficiaries include the Cancer Research Campaign ( pounds 2m), the Royal National Lifeboat Institution ( pounds 1m), the Brooke Hospital for Animals ( pounds 1m), and the Children's Society ( pounds 500,000).