In 'How To Cheat At Cooking', Smith encourages people to avoid making food from scratch using fresh ingredients when they can make use of processed ingredients.

Researchers from Consensus Action on Salt and Health (CASH) analysed the salt content of the recipes in the cookbook -- they found that several contained the recommended daily allowance in one serving.

“Delia Smith is very respected by the public and has great influence over what we cook,” said Graham MacGregor, chairman of CASH and Professor of Cardiovascular Medicine at the Medical School of St George’s Hospital in London.

"She has been trusted by millions of people for years to provide easy, everyday recipes."

“It is a real pity that she seems to be unaware of the dangers of eating too much salt, and furthermore it seems as if these latest recipes have not been checked for their salt content."

Professor MacGregor believes that Delia's use of excess salt threatens to reverse years of campaigning on health.

“The UK is currently leading the world in salt reduction," Professor MacGregor said.

"The majority of our food industry is making huge efforts to reduce the amount of salt they add to food and the public is becoming much more aware that eating too much salt has severe health implications."

"Unfortunately, this hard work is undermined when chefs and cookery writers appear on television using high salt ingredients and adding large amounts of unnecessary salt to their recipes."

"Research suggests that 19,000 deaths from stroke and heart attacks could be prevented in this country each year if we could get down from our current 9g a day to an average of 6g of salt per day for adults.”

Smith's new cookbook and accompanying BBC TV series have already attracted a hailstorm of criticism, with many feeling betrayed by someone who formerly advocated the joys of home cooking with fresh ingredients.

“Nutritionists would always advise people to cook meals from scratch, using fresh ingredients and adding as little salt as possible,” said Carrie Bolt, a nutritionist working for CASH.

"It really doesn’t take long to make a simple tomato sauce from a can of tomatoes, some onion, garlic and herbs."

"Avoiding ready-made versions like tinned mince and jars of sauce would cut the salt content of some of these recipes dramatically."

“If people do want to cook one of Delia’s Cheat recipes -– and they are not all high in salt –- then I would advise them to try the ones that do not feature high salt ingredients such as anchovies, olives, capers, stock, Parma ham, ready-cooked bacon, Thai fish sauce, soy sauce, blue cheese, and Pecorino Romano cheese."

"And there is certainly no need to add any extra salt during cooking.”