A BOLTON schoolgirl started the blaze that killed a firefighter by being "careless and thoughtless" in discarding a cigarette.

But the 16-year-old was cleared of arson because the fire was not started deliberately.

Firefighter Stephen Hunt died aged 38 on July 13, 2013, while tackling the blaze at Paul's Hair World in the Northern Quarter in Manchester.

A police investigation followed, involving interviews with dozens of firefighters, before the Bolton girl, aged 15 at the time, was charged with arson while being reckless as to whether life was endangered.

She was today cleared of any criminal wrongdoing in a hearing at Manchester Crown Court.

But Judge Michael Henshall described her act of discarding the cigarette as "thoughtless", and said its consequences were "terrible".

The girl had been standing outside a fire exit of the salon when she threw down a cigarette end, which was blown through a gap under the door by wind.

Some cardboard boxes that were stacked up against the door on the inside caught fire.

It was initially thought that a naked flame would have been needed to set fire to the boxes, leading to the conclusion that something was lit and pushed under the door.

But further investigations found that there was damage to the boxes through use.

Some may have had paper labels attached, while the application of parcel tape had caused the card to be thinner in places.

This meant investigators could not exclude the possibility that the cigarette caused the blaze.

A "chimney effect" could also not be excluded because it was a hot day and air was rushing through the gap under the door.

Judge Michael Henshall said: "This terrible and tragic case demonstrates the damage and potential damage from discarded cigarettes.

"This was discarded without any thought and as a result a fire started in circumstances which were very particular to the site in question.

"It resulted in extensive damage and the loss of life of a man who, as part of his employment as a firefighter, was there to protect people from fire.

"It was a terrible consequence for a thoughtless act."

He added: "The girl was in fact blameless as far as criminal law is concerned and guilty only of being careless."

Father-of-two Mr Hunt was one of 60 firefighters to tackle the fire at Paul's Hair World in Oldham Street, Manchester.

The ex-soldier got into difficulties inside the building and was taken to hospital but did not recover from his injuries.

He had been living in New Road, Radcliffe, and was based at Philips Park fire station in Manchester.

Alexander Leach, prosecuting, offered no evidence before Judge Henshall returned a verdict of not guilty.

An inquest for Mr Hunt will be held on a date yet to be fixed now the criminal case has ended.