The animal turned on Mandy Peynado and sank its teeth into her arms while she was exercising it at Knightwood Kennels in West Grimstead, near Salisbury.

Ms Peynado was airlifted to Salisbury District Hospital where she is said to be in a stable condition.

Kennel owner Judith Wykeham said she had not been told the abandoned dog may have had a troubled history.

Describing what happened, Ms Peynado's sister, Claire Gourley, said: "She went into the kennels, the dog wanted to play and grabbed hold of her coat.

"She tugged away and he pulled her down and kept on biting and pulling her. He pulled her up and down the pen a few times and just kept biting her.

It did not show any aggression either at the time it was seized or when it was seen at the kennels by our dog warden New Forest District Council spokesman

"To defend her throat, because that's all she was worried about, she put her hands up and that's why she's lost one of her arms."

The dog was later destroyed by Wiltshire Police, who revealed that surgeons were also fighting to save Ms Peynado's other arm.

Ms Wykeham said the dog would have been treated differently if she had known its background.

"Apparently there was a history with the owner who abandoned the dog and the police are investigating," she said.

"We have heard that she'd been banned from keeping dogs for 10 years, but we didn't know this, we weren't told this."

New Forest District Council, which brought the animal to the kennels, said it had shown no previous signs of aggression and was captured as a stray roaming the streets.

Investigation launched

"Whenever we have concerns that a dog may be dangerous, we pass the information on as a matter of course," he said.

"In the case of this dog, it did not show any aggression either at the time it was seized or when it was seen at the kennels by our dog wardens."

A spokesman for Salisbury District Council said environmental health officers were investigating events leading up to the attack to determine whether any breach of law took place.

"Their role is to ascertain the circumstances that led up to the attack and whether there was any breach of health and safety regulations.

"However, the key witness is, of course, the victim herself."