An arson gang torched a house - and then switched off the water supply as firefighters battled the blaze.

Two crews were forced to flee for their lives as their water suddenly dried up with the flames raging around them.

The teenage gang had broken in through a back window and started the blaze - then lay in wait for fire engines to arrive.

And twenty minutes after fire crews had fought their way into the house, they switched off a hydrant 100 yards down the derelict street in Sunderland.

Firefighters scrambled out of the house as the blaze engulfed the property - fortunately they all escaped unharmed.

But the crew said the result of the thugs' actions could have been "devastating".

Police, called in to keep firefighters safe, supervised the scene while they spent 90 minutes battling the blaze.

The brigade has been called to the city's Pennywell estate every day for the past two weeks and firefighters have now called for the boarded-up homes to be demolished.

Leading fireman Warren Mulvaney said: "While the lads were fighting the fire someone decided to disconnect the water supply.

"They got in through the back, removed the steel shutters from a small window, climbed in and set the house alight.

"By the time we got there the flames were shooting through the roof. The hydrant we were using was about 100 yards away and was out of our line of sight."

"As soon as we lost the water we realised something had happened - the repercussions of that can be absolutely devastating.

"It's risking people's lives who are there to fight the fire. Losing your water is the worst thing that can happen to a fireman."

Arsonists have even smashed down walls to gain entry to the dozens of boarded-up houses in the area - just to set them alight.

Firefighters said call-outs to another estate, Doxford Park, once another arson hotspot, have reduced since demoliton started there.

Firefighter Lee Edgar said: "They are all boarded-up, but they are just pulling panels off the doors, getting in and setting fire to them.

"The diggers need to come in as soon as people move out, but it just doesn't seem to be happening.

"Doxford Park has quietened off since they started pulling the houses down.

"We are in Pennywell at least once a day now because there are just constant burn-outs down there."