Blaze under control. INSET: Fighting the blaze.Old Town landmark the Locarno after a huge blaze believed to have been started by arsonists.

MORE than 50 firefighters tackled the blaze during the night after being called out at 3.15pm yesterday.

The roof and part of the first floor have collapsed and the wall at the back of the building is bowing outwards and has partially collapsed.

Fire chiefs have discounted the possibility that other parts of the complex may be in danger of coming down, and the clock tower and the exterior walls are considered safe.

Pete Townsend, station commander at Swindon fire station, said it was the second time in days that the brigade had been called to the buildings. Then youngsters had been seen trying to set fire to the building.

Now the future of the one-time ballroom and Corn Exchange may be in doubt and police have issued an appeal for witnesses to two teenage boys seen near the building before the fire.

Old Town entrepreneur, Gael Mackenzie, who was in Hamburg when the blaze took hold, had planned to develop the buildings to create a caf bar and restaurant alongside an Italian-style piazza on Market Square car park and three apartment blocks in a £1m scheme.

He owns the Town Hall and Locarno buildings while the council owns the adjacent car parks.

Countryside Properties PLC, was planning to develop the area on their behalf and currently has the plans on show in the reception of the council offices at Wat Tyler House in Euclid Street.

If the building is structurally unsafe and needs to be pulled down, it is not yet clear how this may affect the project. Mr Mackenzie was no available for comment.

Last night hundreds of people looked on as plumes of billowing black smoke and flames leapt from the buildings.

Wiltshire Fire Brigade divisional officer, Rob Jackson, said that the rear of the complex looked in most danger.

He said: "The main fire was dealt with in a few hours but because of the danger of further collapse we are unable to get inside. There could be fire hot spots inside, which will mean we can't leave the site for a while.

"We anticipate that fire crews will be here for the rest of today."

The fire is now largely considered to have been put out. The old ballroom area, is still alight and building material has fallen down into the cellar.

Assistant Divisional Fire Officer Steve Williams, confirmed that structural engineers have looked at the building but have not reached any conclusions.

Old Town's High Street, Newport Street, and Marlborough Road were sealed off to traffic last night.

The routes have been re-opened but Old Mill Lane, to the rear of the building, is still closed this morning.

Buildings either side, HSBC bank, and JJ's Hair Group, have not been affected.

Insp Bob Walton, of Swindon police, said: "We are treating the fire as suspicious and are bearing in mind the possibility of arson.

"We are investigating reports of two teenage boys who were seen in the area at around 3.20pm yesterday.

A similar report was received the day before the fire just before 6pm. We will be conducting house-to-house inquiries."

Crews from Westlea, Swindon, Cricklade, Calne, Chippenham, Marlborough, Wootton Bassett and Stratton tackled the blaze.

Council leader Mike Bawden, who is the ward member for Old Town and Lawns, said: "It is an absolute disaster. It is strange it has happened just as the plans have gone on display. The old Locarno looks to me like a write-off. We just hope the old Town Hall can be refurbished.

"I'm not surprised this has happened. It has been a distinct possibility that fire would break out."

Fionuala Foley (Con, Old Town) said she was horrified at the thought of losing one of Swindon's most historic buildings.

She said: "I feel devastated by the fire. The building has such a lot of character, which is sadly missing in the rest of the town."

Photographer Phil Goddard was one of the first eye witnesses and called the fire brigade.

Mr Goddard, of Croft Road, said: "As I came out of the Co-op I could see the smoke coming over the bank and I rushed around to get my camera.

"In a matter of minutes the flames were leaping all over the building. One side was completely covered in smoke."

The many roles of the old building

1852 The Town Hall is built

1886 Corn Exchange opens

1909 Corn Exchange becomes a roller skating rink

1920s the site is transformed into The Rink Cinema

1940s and 50s the Locarno ballroom is at the height of its popularity, before it later becomes a bingo hall

Late 1990s Gael Mackenzie buys Locarno and Town Hall buildings

2000 plans to transform the site into a nightclub fail after magistrates refuse to grant liquor licence

May 2003 plans displayed in Swindon for an Italianesque piazza with apartments blocks, restaurant and cafZ bar

May 18 2003 building semi-collapses after major fire