FIFTY firefighters, who spent almost four hours tackling a Middlesbrough packaging factory blaze, used an unusual method to target the flames.

The fire, at HSG Packing Cases, Nelson Street Industrial Estate, South Bank, was so fierce Cleveland Fire Brigade had to use an infra-red video-link-up with a police spotter plane to track down the source of the blaze.

Twelve tenders were sent to tackle the fire at 10.30pm, on Wednesday, as it tore through cardboard boxes in the corrugated steel building.

Dave Bennett, Cleveland Fire Brigade's head of community fire safety, said a poor water supply meant fire fighters could initially make no impact on the inferno.

He said: "We used the police's downlink system, which allows an infra-red camera to seek out the most severe parts of the fire, which are shown on a portable monitor.

"We were able, therefore, to use our water more effectively. It's probably one of the first times we have done that."

The blaze was contained within a single unit at the end of a terraced block, but the building eventually collapsed when the fire tore off the roof.

Peter Capstick, personnel manager of Bradford-based HSG Packing Cases, said the company, which employs six people in the factory, had already begun looking for alternative premises.

"We will be up and running as soon as is humanly possible.

"We've lost machinery, stock and a couple of vehicles, but our customers in the North-East are especially important to us and we will fulfil their needs in the interim."

Staff from next-door firm Mags Laser Documentation said they were relieved the damage to their premises was not worse.

Director Sean Maynard said: "When we arrived here in the night we were told there was little or no chance of saving our building. Somehow they managed to save it.

"But the back of our building and the side walls are keeling over."

In 1993, the unit at the other end of the same block also burned down.

"We occupy the middle two units and it's happened at either end now.

"We seem to be either jinxed or very lucky," said Mr Maynard.

The joint police and fire brigade arson reduction team yesterday began investigating the cause of the fire