The officer, Carl Hone, collected the female tortoise and took her to the RSPCA's Millbrook Animal Center, in Chobham, England.
The tortoise was not microchipped but a social media campaign resulted in the animal's owner being identified as Catherine Painter.
Painter told officials her tortoise, Sybil, had escaped from her home about 15 months earlier. Painter lives only a few blocks from the garden where the reptile was found.
"Sybil just vanished from the garden one day," Painter said. "We'd been sent on so many wild goose chases that we'd almost given up hope. When a few villagers tagged me into the RSPCA's post about her, at first, I didn't even bother to properly read it. I didn't think it could be her.
"When I spoke to the center and they sent over some photos of Sybil, I was amazed. She looked just the same and even had the same little mark on her shell," she said.
Painter picked Sybil up from the animal center and brought her home to her family, which includes four other tortoises.
"It's so wonderful to have her home," Painter said. "My 5-year-old grandson was so emotional!
"She's got straight back into the routine and made a beeline for the vegetable patch. And she still loves cuddling up with the other tortoises," she said.
Painter said she plans to have Sybil microchipped in case she ever wanders off again.