Two cats found abandoned in a field have been put down after a fatal diagnosis. 

The mother and her kitten were discovered with six others by a farmer in Didlington, near Mundford, on October 17 and taken into the care of Breckland Cats Protection. 

They were later diagnosed with Feline Leukaemia Virus, which attacks the immune system, and were put down after a veterinary examination on Monday morning.

Alison Lardner, a volunteer for Breckland Cats Protection, is now urging anyone who has recently bought kittens from a breeder to get their pets checked for the virus. 

"It's a killer and a long, lingering death," she said. "These cats were too far into the disease to have been saved."

READ MORE: 'Kitten crisis' looms as shelter sees influx of cats

The animals were found sealed inside crates which were secured with zip ties and it is believed they were kept in bad conditions. 

Another of the cats, currently in the care of Ely Cats Protection, is too unwell to be blood tested for the disease. 

Feline Leukaemia Virus is an incurable viral infection that is transmitted through saliva, blood and other bodily fluids. 

Cats can be vaccinated against it but there is no cure. 

Ms Lardner added: "I'm just so angry, I can't get over it.

"This is the result of breeding and the market being so saturated."