The blaze, believed to have been started by a gang of teenage firebugs, has sparked outrage among residents and shop owners in Lawson Avenue, Stanground, Peterborough.

The atrocious act, which bears a smaller scale resemblance to the huge fire in Lakanal House, south London, which killed six people last week, has also been condemned by the fire service.

Witnesses say the fire began at about 4.45pm on Tuesday, when about "three or four" arsonists were seen to pour petrol into the stairwell, after breaking open its secure door.

They then set light to the fuel on the concrete stairs, which lead to The Parade – a line of flats above the shops – before fleeing the scene. The blaze sent smoke bellowing into neighbouring shops, from where staff called the fire brigade.

Co-owner of Head to Toe Carol Johnson, whose business is next door to the stairwell, said: "I was in the salon and we had clients in here, too. The smoke was bellowing in.

"There was two people working here and about three clients. It's not good at all and people are frightened to come down to this area because of incidents like this."

Firefighters from Stanground extinguished the blaze, which had blocked the stairwell, giving residents no route of escape if the flames spread to the rest of the building.

Steven Housden (51), of The Parade, was at home at the time and today spoke of his fears.

"It happened a few weeks ago, too, and I fear for my safety," he said.

"There's meant to be a dispersal order around here. I've lived here for 15 years, but it's getting worse."

A fire service spokesman said the fire put the lives of people living in the flats in "serious jeopardy" and called on anyone who witnessed the blaze to contact police.

"If the fire had not been spotted, it would have spread rapidly and the residents would not have been able to escape. The fire service condemns those who start fires deliberately," added the spokesperson.

Police, who yesterday conducted door-to-door enquiries to gather vital clues as to who may have started the fire, are urging any witnesses to come forward.

If anyone has further information about this incident, or about the person or persons responsible, then call police on 0345 456 4564 or Crimestoppers, anonymously, on 0800 555111.