About 13 teenagers stormed into the Charlton Centre and set off the fire extinguishers last night.

Peter Nix, who arrived at 9.05pm after being notified by a colleague, told the Mercury: "The kids ran out from the fire exit at the front but I went in to check it out.

"I searched the top of the centre but I didn't know if there was anyone else there."

He said that the group were seen outside the centre afterwards, but claimed the police took an hour to respond.

By the time they arrived, Mr Nix said the group had gone.

"It was frustrating, they could have turned up and I could've been on the floor," he added.

A police spokesman said that officers were called reporting that a group of youths were acting "suspiciously."

The spokesman added: "The initial call reported that the group had left the centre and no damage had occurred.

"A further call reported that water fire extinguishers had been emptied and plant pots had been kicked over.

"Officers attended and conducted a search of the area but no persons were found. Inquiries are ongoing."