Jack Sheldon’s badly burnt body was found in a shed at his home on Byron Avenue, Campsall, South Yorkshire, by firefighters who were unaware that anyone was inside.
Coroner Nicola Mundy said she had concerns about fire service systems after a four-minute delay was caused by sending the wrong fire engine to the scene.
Ms Mundy told Doncaster Coroner’s Court that neighbours became aware of the fire on October 27 when they saw smoke.
The inquest heard evidence from a number of people who made “valiant efforts” to put out the fire. But Ms Mundy said: “I do believe that, at this time, this was a fully developed fire and, sadly, it’s likely that Jack had already passed away at this time due to the intensity of the fire.”
The inquest heard that the force control room had received multiple calls regarding the fire and the nearest fire engine was not sent to the incident owing to an “error” when the calls were logged.
Ms Mundy said she did not think the resulting potential four-minute delay had altered the outcome, but she said she would raise the issues with the fire service.