The male dog, now named Reggie, was brought in by a man who claimed to be a friend of the owner.
The man stated he had been looking after the dog for six weeks.
Mystery man disappeared
However, while the staff briefly went to get some paperwork, the man disappeared, leaving the Pug behind.
Animal Rescue Officer Sophie Taylor said: “This poor little pup has been left all alone with no owner to care for him – it must be a scary and overwhelming experience for him.”
The RSPCA is particularly keen to speak with a man seen at the centre during the incident, who may hold vital information.
Reggie’s microchip remains registered with his breeder, and he has not been neutered.
Chronic health problems
A veterinary examination revealed chronic issues in his hind legs, including muscle wastage and reduced sensation, though he is otherwise healthy.
Anyone with information is urged to contact the RSPCA inspectorate appeal line on 0300 123 8018.
The charity hopes the appeal will shed light on Reggie’s past and help ensure his future is much brighter.