Dress fire mystery

Did this woman die from spontaneous human combustion or is there a more logical explanation for her death?

Phyllis Newcombe and her fiancee were leaving the dance floor of a Chelsmford, England, ballroom on the 27th. August 1938 when suddenly her dress caught fire.
The dress, made from crinoline, became a mass of flames, and it was put out with some difficulty. But this  was too late to save her – she died from her burns in hospital a few hours later.
At the inquest it was suggested that a discarded cigarette had set the dress alight. To test this theory, a lighted cigarette was touched to the remains of the dress. It flamed but failed to start a fire.
The coroner expressed his puzzlement and gave a verdict of accidental death.
It is understandable that he was puzzled.
The flames from a a dress that has caught fire cannot produce the intensity of fire that is required to severely burn a body. Only a fire in the immediate surroundings of the body, a mattress for example, can do this.
The only other explanation is, she was a victim of human spontaneous combustion.