FESTIVAL organisers blasted a lout who set off a fire extinguisher during a packed gig and left three people needing medical treatment.

Security staff had to evacuate Boscombe Community Fair after the main marquee filled with smoke that left some people feeling unable to breathe.

Around 200-300 people were cleared out on Saturday night when the show by dance music headliners Subgiant was interrupted after only four songs.

Helen Keeling, 30, a student nurse from Southbourne , said: “There was a boy waving the fire extinguisher nozzle around and laughing.

“It was going into people’s faces and eyes. There was an older man with a handle or pump.

“I grabbed him and as soon as I did that they ran away.

“The smoke seemed to suck the oxygen from the room. It was stinging my eyes and I was coughing. I literally couldn’t breathe, I was just coughing. Everybody was crying.”

The fair is aimed at families and is held on a gated enclosure on King’s Park.

There is folk music, performance poetry, burlesque and art and children’s sessions.

One of the organisers, Bert Burnell, said: “It was just one young lad who ruined everything that night.

“It’s been a great weekend and the vibe was fantastic – we have had lots of families down.

“As far as I can ascertain there was a young lad of about 18 who grabbed a powder fire extinguisher. We just followed procedure which is to make sure everyone is out of the site which went smoothly.

“There were a couple of moments when people didn’t realise what was happening but it was fine.

“The powder was not toxic and anyone with problems just needed a drink of water.”

Dorset Police said they were called around 10.45pm and three people were treated at the scene by ambulance staff for coughs and eye problems.

A spokesman said officers could not establish if it was set off deliberately and it had not been logged as a crime.

Helen Keeling went for a check-up at Royal Bournemouth Hospital yesterday.

She helped evacuate the marquee and said: “There was one person on the floor, people were trampling on him. He was crouched down on the floor struggling for breath.”

One 40-year-old festivalgoer from Boscombe, said: “It was a shame because it was a great day and it was marred by some silly idiot. It was the best Boscombe fair I’ve been to yet.

“The organisers and security were fantastic, they could not have acted faster. There was nobody being trampled on.”

Subgiant’s bass player Olly Maw said at first he thought a smoke machine had been left on but later could not even see the drummer. He said: “The evacuation was quite calm. It was frustrating because it was such a good crowd.”

Festivalgoer Andy Stock, 35, from Boscombe, who also organises music events, said: “It is so difficult to run any commercially viable events so the stupid act of an individual like this can have serious repercussions.”