The early-morning blaze at the fairground in the People’s Park started after a gas cylinder caught fire.
Nine firefighters in two appliances were called out at about 2.20 am on Monday morning.
None of the occupants, who work at the fair, were injured.
Station commander Clive Russell said the fire was being treated as suspicious and police are investigating.
‘We have done our job of identifying that it is suspicious and the investigation has been passed on to the police now,’ he said.
‘From our point of view it is clear that a propane gas cylinder has been moved from an adjacent barbecue.
‘The cylinder has been deliberately rolled under the caravan.’
Following the blaze, watch commander Paul McGrath said it ‘had the potential to be very serious’ and added that his crew stayed at the scene until 4.20 am to ensure the canister did not reignite.
The blaze is not being linked to a recent spate of suspicious fires which are being investigated by the States police.
The force were unavailable for comment before publication.
Anyone with information should contact the police on 612612 or Crimestoppers on 0800 555111.
