A group of children witnessed a woman, who had a dalmatian dog with her, dump the cat in Wileman Street at around 4pm on Thursday, 31 August.
The woman, who had short brown hair, allegedly told the children, “If you want to kill the cat, you could.”
The elderly cat, who has been nicknamed Minnie, was collected by an RSPCA inspector and is still under treatment at a local vets.
RSPCA inspector Natalie Perehovsky said: “Minnie is not in a good way at all. When she was found she was struggling to use her back legs and part of her tail – which was deformed – was missing. She is so thin, dehydrated and weak and has only three teeth. Her paws were stained yellow and she had a lot of matted fur.
“Sadly, her health has not improved since she was found, but the vets are trying their best.
“We are very concerned that she was callously dumped like this. We are urging anyone who has any information about the woman who dumped poor Minnie to contact us in complete confidence on 0300 123 8018.
“We are very thankful to the group of children who raised the alarm after witnessing what must have been a distressing incident.”