Animal welfare officers have vowed to leave no stone unturned in the hunt for a callous dog owner who left the animal to suffocate in a rubbish skip.

Travellers and nearby residents are being urged to help track down the person after the dog died in horrific circumstances.

Seasoned RSPCA Inspector Gary Palmer was reduced to tears as he rescued the half dead, six-year-old Collie.

It had been abandoned in a heavy duty refuse sack, tied with twine and weighted down with concrete posts which had been thrown on top of the pitiful bundle.

"I have dealt with a lot of the worst cruelty cases in this area but this absolutely broke my heart. For somebody to have done this when there are so many people who could have helped is so utterly heartless," said Insp Palmer.

A rail passenger was being dropped off to catch a train at Yarm Station when the person who had provided the lift heard the sound of whimpering coming from a skip and on closer inspection saw movement in a refuse sack.

Insp Palmer said: "The dog was bleeding heavily from the nose. It had been trapped under some concrete pillars which had been thrown on top of it. Due to the extent of its injuries the poor thing had to be put to sleep.

"This was no a road hit, a dead body thrown into a skip. It had been quite deliberately put in there, in a bag to suffocate and covered over with concrete posts; cold and callous," said Insp Palmer.

The collie was black with white markings, a dog and about six years old. The person who left the animal to die could face a jail term of up to six months and or a £5,000 fine. Gary Palmer's colleague, Inspector Laura Plover said: "Our hope is someone will recognise the dog's description and realise it is missing - and phone us."

The case has been highlighted as part of The Northern Echo's Animal Watch Campaign which aims to do something about the region's appalling reputation for cruelty. The telephone number to ring is 08705 555999.