A blaze which ripped through a North-East waste recycling plant on Thursday night is still being probed by police arson investigators.

More than 60 firefighters were involved in tackling the fire at the SWS waste management plant, in Belle Vue, Hartlepool, from 6pm on Thursday to about 9am yesterday.

The flames were spread around the waste paper recycling plant by moving conveyor belts.

A police spokeswoman said last night: "Police arson investigators are looking at the cause of the blaze.

"We should know fairly soon whether it is suspicious or not."

Fire brigade assistant divisional officer Alan Gill said that police and fire crews were working together to discover the cause of the blaze.

He said: "We are keeping an open mind at the moment. It could have been caused by anything."

Eight firefighters were sent in to extreme temperatures to tackle the massive blaze.

Officers from Stranton fire station, in Hartlepool, rushed to the fire within four minutes of a 999 call at 6.20pm.

They were joined by fire crews from across the region.

In total, 65 firefighters and 11 engines attended the incident.

Crews from County Durham were drafted in to cover other Teesside incidents while the factory fire was brought under control.

Last night, Mr Gill praised the firefighters from Stranton's Green Watch, who spearheaded the operation to extinguish the blaze.

He said: "The Green Watch worked over the extremely busy bonfire period and now they have had to contend with this.

"Firefighters outside the building were soaked and freezing cold as they tried to get water to the fire.

"Inside, there were men contending with the intense heat of the fire.

"I think everyone would agree that the fire crews did an extremely good job, despite extreme and dangerous conditions."