AT the age of 70, Delia Smith continues to radiate careful controlled perfectionism.

Whether she's sharing her Christmas routine, describing the inexpensive delights of cooking lamb's kidney in sherry or explaining why she can never agree to a spot on Saturday Kitchen (she's always watching Norwich City), the presenter and author answers each question she's asked with the utmost diligence.

This Christmas Delia's been reunited with Heston Blumenthal on screen in the seasonal Waitrose advert.

They make a deliberately incongruous pair. Blumenthal's eccentrically-filled mince pies contain lemon curd, rose water, apple puree and orange juice (not to mention that pine sugar dusting), while Delia's Classic Christmas Cake Prepared Ingredients box, already weighed and prepared for cooks, replicates the recipe she's been endorsing for years.

"You simply must buy it," she said, in her typically serious manner.

"I just don't think people realise that it'll make them the perfect cake."

While ensuring the nation bakes the quintessential Christmas accompaniment is a pressing concern, she's extremely modest about her effect on our culinary skills.

"Food and cooking have always been the stars, not me. I was just in the background wanting people to understand," she said.

Ever since cooking programme Family Fare launched Delia's television career in 1971, following her first book How to Cheat at Cooking, the cook-turnedauthor/broadcaster came to represent the sensible, edifying face of cookery.

In real life, her style is similarly restrained, a far cry from the relaxed banter-style of her modern successors.

"What's my advice for stressed people at Christmas? Well. . .you need the right cookbook," she said, with a little laugh.

Much of her passion for food stems from a belief that without cooking skills, society as a whole is very much the poorer.

She recalls with horror the educational reforms in the 1980s that effectively pulled cooking lessons from the national curriculum.

"It was a terrible, bad, bleak day. Once all those kitchens and all that equipment is taken out, it's too expensive to put it all back again.

"I once said on a BBC programme, 'We lost cooking when Mrs Thatcher took it out of schools' and they edited the Mrs Thatcher bit out."

"I wish there was some way the Government could give people information about how to get nutrition without spending a lot of money.

"I really would support and do anything I could to help."

She follows this approach in her own Christmas traditions. Instead of presents, she and husband Michael Wynn-Jones donate to a charity.

"It takes all the hassle away," she explained.

When it comes to festive food, however, Delia freely admits to indulging in excess.

"I use my own book. I just open it and say 'Right, at 4pm you do this. . .'

"That Christmas Day page, the person it's really for is me. Because you only do it once a year, you're not going to remember anything.

"So you open and it says, 'Do this now, do that then' and then it's all done. It's like being on automatic pilot."

According to her own instructions, Delia puts the turkey in before she heads to mass on Christmas morning, and finishes the preparation on her return.

"We have Christmas lunch at lunchtime because otherwise the day is gone. Far too much is eaten and far too much is drunk, but I love it.

"I go out and buy all these special things. For example, New Year's Eve is the only time of year I will drink a single malt whisky because it's Scottish. And we'll have the best champagne we can have. You know, really treat ourselves."

She's spent just one Christmas away from home in the last few decades, preferring to hunker down in Suffolk with husband Michael, who she met while working at the Daily Mirror more than 40 years ago.

Although she draws the line at posh chocolates.

"Cadbury's Fruit and Nut from the freezer does something that is extraordinary!"

And if you are now in the mood to get festive party started why not try some of Delia's canape recipes?

Recipes adapted from Delia's Happy Christmas published by Ebury, priced £25.

Visit deliaonline.com for more recipes