The Great British Bake Off contestant Marie Campbell has come under intense scrutiny, after it was revealed that she is not quite the amateur baker the BBC show claims. In reality, she has trained at a world-renowned French culinary school and run her own baking-related business.

The investigation by the Mail On Sunday discovered Campbell had been professionally trained when she was younger by top chefs at the prestigious Ecole Escoffier at the Ritz in Paris, concentrating mainly on pastries. She went on to teach classes to aspiring chefs in Glasgow and ran the award-winning Duisdale House Hotel and restaurant on the Isle of Skye.

It was also disclosed that in recent years she has managed a business called Mrs Campbell's Cupcakes, creating cakes and other confectionery, which she sold online from her home in Auchterarder, Perthshire.

In the run-up to the sixth season starting last week, which was watched by 9.3m viewers, the introductions to this year's contestants merely described Campbell as someone who was "inspired by French patisseries and their decorative creations" when it came to her baking beginnings, as well as saying that she's come a long way earning herself a place in the competition as when her children were little, "she couldn't even boil an egg". But despite never mentioning it in their promotional material, Campbell confessed last night (9 August) that the show knew about her baking history. "Love Productions knew about my patisserie training, which was only for a week and was a long time ago," she said.

The retired 66 year old triumphed over her fellow bakers in the show's highly anticipated first episode, being crowned star baker by judges Paul Hollywood and Mary Berry, for her near-perfect Madeira cake and well-executed Black Forest gateau. She has also already been tipped by Ladbrokes as the favourite to win the competition, which has always prided itself on being a contest that pits amateurs with a passion for baking against each other, rather than professional chefs. Her odds currently stand at 3/1. However, last week, bookmakers were forced to suspend all bets as a number of sizeable punts were placed on one contestant, worrying both the show and betting shops that the winner's name had leaked, as the series has already completed filming.

Also last night, a BBC spokeswoman detailed that even though Campbell has in fact run a cupcake business in her past, it never acted as her main source of income and therefore is not regarded as a professional. "There are strict criteria to taking part in the show and Marie met that criteria. She gained a certificate for one week's training in Paris in 1984."