Animal rescuers in Britain said a man who brought a stray puppy home from a construction site later discovered the animal was actually a fox cub.

The RSPCA said the worker found the baby animal at the building site in Merseyside and took it to his home in Speake, where he soon realized it was a fox cub and not a domestic dog.

Animal Welfare Officer Matt Brown retrieved the cub from the man's house.

"The worker was on a building site in Speake when he came across what he initially thought was an abandoned puppy and as he could see no mother around he took him home," Brown said. "But when someone told him it was not a pup but actually a fox cub he rightly called the RSPCA."

Brown said the cub, which appears to be under a month old, is in the care of veterinarians and will later be taken to the RSPCA's Stapeley Grange Wildlife Center in Nantwich.

"In most cases females will return and collect their cubs if given the opportunity, and it's not unusual to see older cubs above ground on their own during the day learning survival skills and the parents are usually nearby," Brown said.

He said the cub will eventually be returned to the wild.