Four were taken to hospital after the fire

The heat from the flames was so intense that the window frames of the flat in Port Talbot, south Wales, melted and neighbouring flats were badly damaged by smoke.

The elderly owner and three others were treated at Neath Port Talbot Hospital for smoke inhalation.

The incident happened on Moorlands Road in the Sandfields estate.

Two fire appliances from Port Talbot fire station attended the fire, which was reported at around 1910 GMT.

This will no doubt add to the current debate about the sale and use and possession of fireworks Bob McAlister, South Wales Police

The flat was well alight when they arrived.

Superintendent Bob McAlister, of South Wales Police, said " On the face of it this would appear to be another totally irresponsible and dangerous act with a firework.

"The damage could have been worse but on this occasion, were it not for the prompt action of the fire service and the alertness of the residents.

"This will no doubt add to the current debate about the sale and use and possession of fireworks.

"We will vigorously pursue whoever is responsible and I would ask for any information about the culprits to be given to us".

Residents of the flats said they felt lucky to have escaped the fire.

Karen Bailey said: "I looked out of the window and saw everyone outside and I thought I'm in here and they're out there.

"I thought that these flats were going to blow up and I'm going to go with them.

"I though I was dead tonight."

The fire is the latest in a series of incidents involving fireworks across Wales in the weeks leading up to Bonfire Night.

Residents search for their belongings following the blaze

Last month, a disabled grandmother was injured when a firework smashed through her double-glazed window and exploded in her front room.

Marjorie Davies' hair caught fire when the 2ft rocket went off at her house at Bryn Golau, Llanelli, as she watched television.

Her husband Ken Davies, who was in an upstairs room, rushed to help and had to throw water over her and the burning chair she had been sitting on.

The grandmother-of-six also suffered cuts to her face and hands, perforated ear drums.

The next day, a telephone box in Rhondda, south Wales, exploded after fireworks were lit inside.

The number of injuries from fireworks continues to grow.

Last year, 73 people were treated for fireworks injuries at NHS hospitals in Wales, up from 64 the previous year.

Bangers were the main causes of injury with the number rising from six in 2001 to 17 last year.

Nearly half of all injuries (33) occurred to children under 15.