The residents were given shelter in a nearby school because there were potentially explosive gas canisters inside the garage.

Fire ripped through The Crescent Garage, on Devonshire Crescent, Roundhay, Leeds at 7.30pm yesterday where there were reports of a number of cylinders containing highly flammable acetylene gas, inside.

Today it was confirmed that the fire was being treated as malicious.

The garage was closed at the time the fire started and no-one was injured.

Det Insp Adrian Taylor said it was believed the fire was started after someone pushed something through the letter box of the office door at the garage.

Police were today carrying out house-to-house inquiries, and urged anyone who saw anything suspicious to call them on 0113 241 3659.

More than 25 firefighters tackled the blaze – which gutted the building – while police evacuated residents from streets surrounding the site which were then sealed off. A meeting at nearby St Andrew's Church was also disrupted, and a 200m exclusion zone was put around the garage.

Police alerted the caretaker, of Allerton Grange High in nearby Talbot Avenue who opened up the school where around 60 residents gathered for 90 minutes while the fire scene was made safe.

Francis and Ethel Harman, aged 88 and 80, of Devonshire Crescent, said they feared they would have to stay in the school overnight. "We saw people there with sleeping bags and pillows and we got worried," said Mrs Harman. "Some people were cuddling babies who were fast asleep and I saw someone holding a kitten. We were so worried they would keep us in overnight."

Antoinette Peters lives on Sutherland Avenue, near to the garage.

"Everyone was walking and driving away from their homes down to the school for safety. You could see the whole roof on fire and the flames were going up into the air. I could see smoke billowing up and flames coming out the roof. I did feel quite worried about what was happening."

The area was made safe at 10pm and the residents allowed back home.

Moortown watch manager Richard Cockx said the gas cylinders had been removed about two hours after firefighters were called to the blaze.

"The problem with acetylene is that it becomes very unstable when involved with fire and can level a large area if it explodes," he said. "Once we had removed the cylinders the residents were able to return to their homes."