It is appalling that someone could do that

PC Martin Cowen

PC Martin Cowen said the horse's owner, who is from the local travelling community, did not wished to be identified but was "extremely distressed" by the incident.

The officer said the animal - which did not have a name - was one of seven grazing in the area when it was attacked.

The horse had been stabbed twice, and so forcibly in the neck that the blow damaged bone, causing considerable loss of blood.

PC Cowen said he was keeping an open mind on the motive, but he doubted the attack was inspired by a grudge against travellers as the stallion was the only horse that was injured.

He said: "I don't think it was an act of rational thought, it just seems to be an act of craziness or drunkenness.

"It is appalling that someone could do that."

Attacks on horses in the Middlesbrough area were rare, unlike other parts of the country where animals in fields had been slashed and mutilated, he said.

"This is wanton vandalism against a living thing that is completely defenceless."