A teenager charged with arson after a fireman died in a city centre blaze has walked free after the charge was dramatically dropped, three days before she was due to stand trial.

A judge said she was ‘blameless’ as far as criminal law went but ‘guilty only of being careless’ after a court was told the fire was possibly caused by a discarded cigarette.

The 15-year-old was due in court on Monday at Manchester Crown Court to stand trial, accused of arson - reckless as to whether life endangered.

But after a meeting of Crown lawyers, police, and the Crown Prosecution Service it was decided not to progress the case.

The girl was summonsed to court after firefighter Stephen Hunt died in a fire at Paul’s Hair World in the Northern Quarter.

Mr Hunt, 38, a father-of-two, from Whitefield, Bury, was one of 60 firefighters who battled the shop blaze on July 13, 2013.

Alexander Leach, prosecuting, told the court this afternoon that new scientific evidence had come to light which meant the crown could not rule out accidental ignition.

He said “This is a case in which a fire was caused at Paul’s Hair World on Oldham Street in the city centre.

"The prosecution case against this defendant was based on initial scientific findings which indicated the fire had been set by the application of a naked flame on to cardboard boxes.

"Further scientific evidence has been conducted which means that accidental ignition by the application of a discarded cigarette now cannot be excluded.”

Mr Leach said there were some damaged cardboard boxes behind a fire door where the fire began.

The court heard there was a gap beneath the door on the hot day when the fire began and a potential ‘chimney effect’ could not be ruled out.

“The conclusion is, therefore, that the Crown’s case can no longer be sustained and we will now be offering no evidence.”

Judge Michael Henshell said the case involved “terrible and tragic” loss of a firefighter and indicated the danger of discarding cigarettes.

He said:“The girl who was facing a trial was in fact blameless as far as the criminal law is involved and guilty only of being careless.”

An inquest will now be held later in the year into Mr Hunt’s death.

Ninety fire fighters have been interviewed by police in an investigation into his death.

Mr Hunt and a colleague got into difficulties while fighting the blaze and he was taken to hospital but could not be saved.

(Image: Greater Manchester Fire and Rescue Service/PA Wire)

Fire and police launched a joint investigation into the cause of the fire and two 15-year-old girls were arrested and bailed pending further enquiries.

Just one was charged over the fire.

Mr Hunt’s family are understood to be angry because of the time taken on the case as the anticipated court proceedings have considerably delayed the inquest.

A fire brigade source said: “Now the family must wait even longer to finds out the the truth.”