A major fire has ripped through a mill building in Bradford city centre which was being re-developed as a £25 million residential and leisure complex.

Fire crews from across the district were called to the blaze at the Woolston Warehouse in Sunbridge Road at 12.30pm yesterday.

Flames shot from the roof as a crowd of onlookers gathered to watch.

More than 100 firefighters were involved in tackling the blaze. A group of workmen, who had been carrying out some demolition work, had to be evacuated from the building.

Fire crews used an aerial platform to tackle the blaze from above and surrounding roads were cordoned off.

A thick plume of black smoke continued to billow into the air more than an hour after the blaze broke out and burning timbers could be seen following the collapse of the roof of the building.

Firefighters managed to contain the fire and prevent it spreading after about an hour and a half.

Keith Robinson, Bradford district manager for the West Yorkshire Fire Service, said firefighters had to remove gas cylinders from the building as they were at risk of exploding.

Fire crews remained at the scene into the night to damp down the blaze.

Mr Robinson said it was likely that the blaze was caused by an accident involving the work being carried out on the building.

He said: "We're not suspicious, obviously contractors were on the site and hopefully the cause will be an accidental fire."

The new development, near the junction with Vincent Street, is set to include 250 homes, boutiques and leisure facilities and is due to be completed by mid-2009.

Last night Paul Ellis, managing director of The Skelwith Group, which is developing the site alongside Wakefield-based Aspasia Group, said: "We are aware of the situation and are pleased that the fire is now under control and not a threat to neighbouring properties.

"It is too early to say any impact on the development timetable but we remain committed to this key regeneration project at this significant site for the city.

"We are disappointed because more than 70 per cent of units have been sold but we are confident we can resolve the problems and get construction back underway."

Demolition Services Ltd, the company on site at the time of the blaze, was unavailable for comment.

e-mail: tanya.orourke @telegraphandargus.co.uk