Mary Berry talks The Great British Bake Off

If you haven't caught the baking bug yet, you need BBC2's The Great British Bake Off.

Since 2010, sales of bakeware - cake tins, muffin trays, wooden spoons and the like - have risen by 39% at Sainsbury's, and in the last year alone sales of Union Jack cupcake cases at the supermarket have shot up by a whopping 2,050%.

The TV baking contest, which is returning for a third series, is thought to be one of the driving forces behind our love affair with all things doughy.

"I think it's lovely," says cookery expert Mary Berry, who judges the show alongside master baker Paul Hollywood.

"Everyone who enters is an amateur, so people at home look at them and think 'I could do that'. Mothers and fathers are baking with their children, and uncles, aunts and grannies are doing it. Lots of schools and offices are having bake offs now and it's all to do with the show. It's stimulated Britain to bake."

The programme, fronted by Mel Giedroyc and Sue Perkins, sees 12 amateur bakers battle it out to produce the best cakes, breads and pastries.

This year the varied batch of contestants includes 20-year-old medical student James, from the Shetland Islands; Irish-born company director Brendan, aged 63, and 28-year-old vicar's wife Sarah-Jane from West Sussex.

"The show's getting bigger and better and the standard is marvellously high this year. Higher than ever before," says Mary.

A tense affair

Tensions regularly bubble over on the programme, as the bakers anxiously watch their ovens, and Ms Berry is careful to be as constructive as possible in the judging process.

"I'm extremely fair. I want to encourage them to bake more and don't want to frighten them off. I don't want them to cry if they don't do it right."

Despite her years of cooking experience, she insists she learns "all the time" from the contestants.

"They're very modern with their colourings. One used freeze-dried raspberries the other day - I'd never seen those before - and they use the internet and come up with all sorts of creations.

"I learn so much from Paul too because he's a brilliant bread maker. He's taught me to always make a wet dough."

With so many tempting treats to sample, Mary has a small mouthful of each. "But the next day I'm pretty careful," she adds, when quizzed as to how she manages to stay so trim.

The 77-year-old is adamant she will never resort to cosmetic surgery, but admits she worries about her appearance in front of the show's millions of viewers.

"Obviously I want to look good," she says. "You'll always see me blonde, I'll tell you that much, and I bother about my nails. The rest looks after itself."

A word from last year's winner

Mild-mannered mother-of-three Jo Wheatley says winning the 2011 show changed her life "massively". The Essex native now runs her own cookery school from home and has released a book of baking recipes.

"It's been a wonderful experience and a huge confidence boost," she says.

"It's so nice to have a job where one day I might be doing a demonstration, another I'm at home writing recipes and another I'm teaching. It's such good fun."

She can fully understand why the rest of the nation seems to have cottoned on to the hobby she's been enjoying for years.

"With the recession, baking is something everyone can do. It can be as expensive or inexpensive as you want it to be.

"As long as you've got some eggs, flour, sugar and a couple of basic pieces of equipment, you can bake.

"And if you bake yourself there are no E numbers or preservatives so you know exactly what you're feeding people."

The Great British Bake Off returns to BBC Two from Tuesday August 14