Three masked men were foiled in their bid to steal a cash box from a slimming class when a woman group leader turned on them.
The raiders burst into a Slimming World meeting in Harpurhey, Manchester, and one of them ran across a hall to grab the evening's takings but the group's leader picked up her chair and used it to knock him to the floor.
Police said the thief then dropped the box and all three offenders ran out of the building.
The leader was one of six women who were in Holy Trinity Hall discussing plans for Christmas after the class ended when the raiders struck at about 9pm on Monday November 19.
The first man is described as slim, white and about 6ft. He had something covering his face which was dark in colour with a light-coloured stripe around the top. He wore a body warmer with a light blue-coloured top underneath.
The second man is described as about 5ft 6in, average to well-built. He was wearing a gilet and had a balaclava covering his face.
The third man is about 5ft 4in and of average build. He wore a blue gilet with a red and white knitted jumper underneath and also had a balaclava covering his face.
All three were in their late teens to early 20s.
Detective Constable Kelly Featherstone said: "These men had the audacity to run into a meeting to try to steal the club's takings.
"They were probably not expecting the team leader to put up the fight she did, meaning that thankfully they were not able to get their hands on the takings."