Pet-owners are being warned to keep their cats indoors following a spate of poisonings.

Vets at Terrington Veterinary Centre have sounded the alarm-bell after treating a number of felines who have swallowed anti-freeze. Kim Coward, a registered veterinary nurse at the centre, said up to seven cats have been treated at the centre in the last two to three weeks - all from the Sutton Bridge area, west of King's Lynn.

She said it was possible that the substance is being used in a deliberate attempt to target cats.

Anti-freeze is toxic to cats, but carries a sweet smell which attracts the animal.

Miss Coward said the majority of cats who drink anti-freeze do not survive. This has been the case in the recent incidents at Sutton Bridge.

'Nine times out of ten it is very difficult to treat cats that have swallowed anti-freeze,' she said.

'It does lead to fatality in the majority of cases.'

Miss Coward is therefore urging cat-owners to keep their pets indoors until the incidents stop.

'The owners have obviously been worried and upset about what's happened to their pets,' she said.

'It's possible that people are using anti-freeze maliciously.

'But it could also be spillage from people using the substance for their cars now that we're approaching winter.'

Antifreeze mixes with water to prevent water from freezing. It also reduces corrosion in the car's engine and helps avoid overheating.

Symptoms of a cat having drunk anti-freeze includes lethargy, the inability to stand up, wobbliness, loss of appetite, and frequent licking around the mouth.

Miss Coward said it was crucial for pet-owners to take their cats to the vet straight away if it is exhibiting any of the symptoms above.