1978, August 22: West Cornforth Woman’s Fiery Death
At 5:00 AM on August 22, 1978, a 6-year-old girl discovered her mother's incinerated remains in the basement of their home in West Cornforth, Durham, England. The woman was 33-years-old, and the room itself was little damaged. It was suggested that she was depressed and that nervous tremors had caused her to accidentally knock over a heater and set herself on fire.
This is the first listing of this incident in Anomalies, and therefore will require more research to confirm it. This is especially true because the above comes from Jenny Randles and Peter Hough's 1992 book, Spontaneous Human Combustion; this book gives almost no sources for the accounts it relates, in this case attributing the above to "Author's own investigation"... which essentially means "Just trust us." For this reason, this account is marked as both "Unreliable" and "Investigate;" I will add new information as I get a chance to dig further.
With the details above,this case does not sound very supernatural; what is needed is a better assessment of how damaged the mother was, and how much time was involved.