Spectators at a traditional Bonfire Night parade in Devon were engulfed by flames after a youth threw an aerosol can into a flaming barrel of tar.

At least a dozen people needed hospital treatment for burns after being showered with burning pitch when the aerosol exploded.

Flaming barrels of tar have been paraded through the streets of Ottery St Mary on Guy Fawkes night for hundreds of years but it is believed this is the first time there has been a significant number of injuries.

Witnesses claim they saw a youth throw the aerosol into the barrel moments before the explosion.

The search for the culprit has extended to the internet, with a Facebook group called “Tar barrel aerosol thrower to be brought to justice” attracting 1,758 members in its first 48 hours. Other internet users are comparing photographs and videos taken at the event.

Ian Chown, 23, from Ottery St Mary, was told that he would need reconstructive plastic surgery after a he was struck in the face by burning tar. He was treated for first and second degree burns at a specialist unit at Frenchay Hospital in Bristol.

He said: “I’m just trying to come to terms with what happened. I was stood about three or four rows away when it exploded. I don’t know what hit my face but it was burning me. I managed to rip it off.

“I’m in a lot of pain from the burns. I’m a local and just hope this doesn’t jeopardise the future of this event.

“It has been quite traumatic. I’m trying not to think about it as I don’t want to relive that moment.”

A man who was carrying the barrel on his shoulders collapsed when it exploded.

Jon Watling, 23, who suffered burns to his hand, said:”I got up to see everyone on fire — my coat was covered in burning tar. People kept coming into the casualty tent. There were 15 to 20 in there at a time.”

Graham Rowland, one of the organisers of the parade, said:”Whoever did this was an irresponsible idiot. We put so many safety procedures in place but how can you control something like that?”

The incident has led to calls to cancel the event, which local historians believe dates to the Middle Ages. Burning barrels, each weighing up to 30kg, are carried through the streets of the town but in recent years the event has been under threat by the increasing cost of public liability insurance.

One man said:”This event has now run its course. It’s now time for this very dangerous event to be placed into the history books and stopped for ever. Councillors will be held liable and taken to court for corporate manslaughter when a member of the public is killed. It flies in the face of all health and safety laws.”

Posters leaving comments on Facebook, however, said that the event should continue. One poster said: “I’m completely disgusted and very angry and upset that some complete idiots have not only injured some of my best friends but could have also ruined what should be a fun night and a tradition that is hundreds of years old.”

The incident is being investigated by Devon and Cornwall police, who are studying footage filmed in the minutes leading up to the explosion.

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