Mari Parker, of Darton, works at Barnsley Antiques Centre, which is owned by her son Daniel.
The 72-year-old, who works most days of the week at the shop on Doncaster Road, was taken aback after wrestling with a man who allegedly tried to sell a stolen bike.
“It was just a normal Sunday morning, I was in the shop when a man came in and asked if we wanted to buy a bike for £150,” said Mari.
“The thing was, we had seen it on the Barnsley Stolen Bikes Facebook page, so I told the guy to wait for a bit until my son arrived.
“When my son came in, he told the man we would be
taking it off him as it was stolen.
“It all seemed okay and the guy left, but later on he came back and asked if there was a reward for it and that he was taking it back.
“I was adamant he wasn’t and when he picked it up I walked up and took the other end.
“I was determined not to let go, and we ended up going through the door and we were fighting outside.
“When my son was there he phoned the mum of the boy whose bike it was and asked them to come pick it up, so I thought that there was no way he was getting away with it.”
Mari managed to keep hold of the bike throughout the entire incident, before the man threw her against the side of a van and walked away without it.
The incident was recorded on CCTV and posted online, and it has since gone viral.
“Afterwards, my fingers were all cut and bleeding, my hands were cut and a few days after I was really achy, but I am quite fit for my age,” said Mari.
“Somebody else my age might have been a lot more injured.
“I don’t think it was brave but I think if I had have let go I would have fallen on the floor and that would have been worse.
“It is scary being attacked but I am making light of it now.”
The video of the CCTV has had 8,400 views and 5,300 comments so far, with people from all over the world praising Mari for her bravery.
A spokeswoman from South Yorkshire Police said it was ‘not clear’ whether the bike was stolen.
“Police received a report of a suspicious individual at the Barnsley Antiques Centre on Doncaster Road,” they said.
“It is reported that a man entered the premises and was abusive to staff, before leaving and taking a bicycle.”