Britain's favourite amateur baking show began only last week but already, scandal has erupted over the hot favourite's alleged professional training.

Marie Campbell won star baker in the first episode of The Great British Bake Off on Wednesday after impressing judges Mary Berry and Paul Hollywood with her Madeira cake and Black Forest gateau.

But it has since emerged that there might be a reason why the 66-year-old grandmother seemed head and shoulders above the rest of the competition - the Mail on Sunday reports that Marie once attended the famous Ecole Escoffier at the Paris Ritz for a patisserie course before running an online cupcake business and leading classes for other chefs.

However, before Marie's culinary past becomes the next Baked Alaska (#bingate, Iain Watters throwing his dessert in the bin...never mind), the BBC has confirmed that she is not breaking the rules by taking part in the series.

The Great British Bake Off 2015: Meet the 12 contestants Show all 12 1 /12 The Great British Bake Off 2015: Meet the 12 contestants The Great British Bake Off 2015: Meet the 12 contestants Nadiya, 30 Full-time mother of three Nadiya lives in Leeds with her husband. Born in Luton to a Bangladeshi family, she grew up wondering why her father only sold ice cream as a desert in his restaurant, as deserts aren’t a major mealtime in Bangladesh, so she soon got out a whisk to make her own BBC The Great British Bake Off 2015: Meet the 12 contestants Marie, 66 This year's oldest contestant, Marie was entered by her daughter who claims the baker couldn’t "even boil an egg" while she was growing up. The turning point was when she moved to Paris and was inspired by the patisseries. We’re expecting some amazing croissants BBC The Great British Bake Off 2015: Meet the 12 contestants Alvin, 37 Father of two, Alvin is originally from the Philippines but now works as a nurse in Berkshire. According to the BBC, he’s a true perfectionist who once repeatedly baked bread each day for three weeks until he got it just right BBC The Great British Bake Off 2015: Meet the 12 contestants Dorret, 53 Originally from the West Indies, Dorret actually grew up in Preston and now works as an accountant. She enjoys hosting dinner parties with her husband to “impress their friends with their skills” BBC The Great British Bake Off 2015: Meet the 12 contestants Flora, 19 The youngest baker in this year’s competition, Flora is an assistant at a contemporary art gallery and is currently waiting to start her history of art degree. Expect some tastefully arranged cakes BBC The Great British Bake Off 2015: Meet the 12 contestants Ian, 41 Travel photographer Ian lives with his wife and two children in Cambridgeshire. Recently, he’s become more of a house husband, making his family fresh bread every day, but that doesn't stop him being the Dalai Lama's personal photographer when he's in the UK BBC The Great British Bake Off 2015: Meet the 12 contestants Mat, 37 Fire Fighter Mat began baking three years ago in between work shifts and is a self-confessed “competent amateur” who “learns every time he bakes”. His ambition, apparently, is to one day own a dishwasher BBC The Great British Bake Off 2015: Meet the 12 contestants Paul, 49 Prison governor Paul sees being on the show as “an opportunity to show that men like me, stereotyped by our jobs do and can love baking and that it is a skill and talent to be proud of.” The Welshman also enjoys exploring the countryside with his wife and three sons BBC The Great British Bake Off 2015: Meet the 12 contestants Sandy, 49 Mother of one, Sandy is a child welfare officer who lives near Bradford. Describing her baking style bluntly, she said: “it might not be glamorous but it’s tasty” BBC The Great British Bake Off 2015: Meet the 12 contestants Stu, 35 Professional musician Stu has toured the world, and according to these photos, has a hat surgically attached to his head. The lead singer used to watch his parents in their restaurant and was amazed “how something liquid could go in and out would come this fluffed up awesomeness” BBC The Great British Bake Off 2015: Meet the 12 contestants Tamal, 29 Tamal’s parents moved from India to Hertfordshire in the 1960’s, his older sister soon teaching him to bake. He is now a trainee anaesthetist in Manchester, and once baked a five tier wedding cake BBC The Great British Bake Off 2015: Meet the 12 contestants Ugne, 32 Originally from Lithuania, Ugne’s main hobby may be baking but she is primarily a bodybuilder. She lives in Essex with her partner, also a bodybuilder, and two children. She's the one who said cake is a "nutritional sin" BBC

The Bake Off entry form states that contestants must not have earned any professional catering qualifications within the last decade, but Marie trained over 30 years ago.

The rules also stipulate that contestants must not depend on "commercial baking in a professional environment" as their main source of income and they cannot ever have worked as a full-time baker or chef.

"There are strict criteria to take part in the show and Marie met those criteria," a BBC spokesperson said. "She gained a certificate for one week's training in Paris in 1984, more than 10 years ago. She has not worked professionally as a baker or chef."

Marie will not be commenting herself.

The majority of this year's contestants run their own baking blogs and Instagram feeds where they show off some impressive creations.

More than 10 million viewers tuned in to the Bake Off's opening show, which saw Stuart 'Hipster Stu' Henshall booted off after Mary turned her nose up at his edgy beetroot sponge.