Survivors of the fire at Bradford City on 11 May 1985 have told a BBC documentary programme about the moment the flames took hold in the wooden stand at Valley Parade in which 56 people died.
The documentary, "Missed Warnings: The Bradford City Fire", also hears from a former West Yorkshire detective who says he interviewed an Australian man who admitted accidently dropping a cigarette during the game between the Bantams and Lincoln City.
The official inquiry concluded a discarded cigarette or match was the most likely cause of the fire.
Missed Warnings is on BBC1 in Yorkshire and Lincolnshire at 22:45 BST on Tuesday, 12 May. It is repeated across the country on BBC2 at 23:20 BST on Wednesday, 13 May.