An 81-year-old great-grandmother is tearing up the rule book on ageing by attending aerobics classes three times a week and taking on a two-hour aerobathon.

Marianne Dean, from Woodside in Telford, joined the two-hour aerobics session, saying she passed it “with flying colours”. The pensioner also took part in Race for Life in Telford when she was 78 and ran the Telford & Wrekin Primary Care Trust Fun Run.

Not content with all that, Mrs Dean, a grandmother of 10, has been known to take over her aerobics class when the instructor cannot make it.

She said: “I think it is probably unusual for someone my age to be doing this, but I’m not on my own, I’m sure there are other people across the county who do take part in exercises at this age.

“And I feel better after doing it. Sometimes you get up in the morning and you could think that you don’t want to go out today, but when you exercise you feel great afterwards – come and give it a try.”

Her current aerobics teacher, Cheryl Jauncey, said: “She is a marvellous lady.

“She is simply amazing and she comes to my over-50s class, and some of my normal classes.

“She gets down and does stomach crunches at 81, she’s brilliant.

“People who come to the class are astonished she’s 81, they can’t quite believe it and she still steps in for me if the odd time I can’t make it.”

Mrs Dean is no stranger to aerobics because she taught it for more than three decades – until she was in her 70s.

“I started to keep fit in the early 1970s and after that I started my own aerobics class at Woodside Community Centre and we took part in competitions around the county,” she added.

“We also had a display team and we used to perform at things like garden fetes and carnivals.

“I’m sure many Woodside residents would still remember it.

“I ran the class up until I was 72 and retired in 2001,” she added.

“Even though I retired I could not give up exercise so I joined Cheryl’s class and I manage it three times a week.”

She added: “But I shall stay with it as long as I can and I’m still quite agile.”

The over-50s aerobics class trains in Jubilee house in Madeley.

They are hoping to raise about £500 for the County Air Ambulance after their two-hour aerobathon last month.