THE RSPCA has admitted it has been left puzzled over a mystery illness affecting cats in a North-East town.

Cat owners on a Darlington estate are keeping their animals indoors amid fears that a poisoner is at work in the area.

Several cats on the Firthmoor estate have suffered a mystery illness in the past two weeks. Symptoms include fits, dilated eyes, twitching and high temperatures.

The animals affected all live in the Pateley Moor Crescent area, and owners fear they might have been poisoned.

But RSPCA inspector Garry Palmer said he has carried out investigations and nothing has so far led him to believe that the cats are being maliciously poisoned.

He believes the animals may have come into contact with some sort of toxin which has not been left out deliberately.

"There are a lot of houses which have been demolished on the estate and because cats tend to roam, they may have inadvertently come into contact with a poisonous material," he said.