Three teenagers who died when a garden shed they were sleeping in caught fire had been warned about using candles in their makeshift den.

Three teenagers who died when a garden shed they were sleeping in caught fire had been warned about using candles in their makeshift den.

Matthew Collins, 17, and Christopher Williams, 13, were sleeping in the hut at 14-year-old Blake Mountney's home in Kingstanding, Birmingham, in March. The three died of smoke inhalation after a candle apparently overturned and set fire to inflammable materials while the boys were asleep.

They had been using the wooden hut as a den to smoke, chat and listen to music and the inquest at Birmingham coroner's court yesterday was told that Blake's grandfather Leslie Hobson had warned them about using candles.

A police statement from Mr Hobson that was read to the court said he had warned them "a million times" about being in the shed with candles.

Giving evidence, Mr Hobson said he had taken the locks off the shed two days before the fire but was unaware that the boys had replaced them with bent nails.

Recording a verdict of accidental death, the coroner, Dr Richard Whittington, said: "The fire took hold immediately. It became an inferno. It was quite impossible for anyone to get out especially as they were trapped by a primitive locking mechanism. As soon as this fire developed they would have been unable to release themselves."

West Midlands Fire Service investigations officer Clive Gregory said sleeping bags and wickerwork chairs inside the shed might have contributed to the blaze.

He said: "The naked flame of the candles had ignited combustible materials inside the shed and it had rapidly developed and that would have produced toxic flames and smoke. [The shed] would have been totally engulfed.

"One or two of the boys may have been asleep and not known what was going on. They would have been unable to get out. If they had been fully aware, they would have been able to smash their way out of the shed."