A cleaner found the young, female, black cat on a new housing development in Kempton Drive, the RSPCA said.
She had a long, white shoelace around her neck which was double-knotted so tightly the RSPCA officer had problems removing it.
The RSPCA said it is thought the cat was alive when she was hanged and the person responsible must have intended to kill her.
Animal welfare officer Jayne Fuller said: "Knowing that someone could be so cold and calculating to hang this cat makes me feel sick.
"The person responsible knew exactly what they were doing and for some absurd reason clearly their intention was to kill the cat.
"The cat must have been friendly and placid to have gone to the individual and for the person to then abuse this animal in such a way is horrific."
Anyone with information is asked to contact the RSPCA following the discovery of the animal last month.
Source: BBC news
(Cat pictured is of similar looks to the cat found)