TH Huxley described science as “the slaughter of a beautiful theory by ugly facts”. The same might be said of biography. It turns out that the famous Mrs Beeton (she of the eponymous cookbook) couldn’t cook and didn’t write it.

If Mrs Beeton had been alive today she would be in trouble for plagiarism on a shocking scale, the Guardian Hay festival heard yesterday.

The image of the original domestic goddess and author of the definitive book on cookery and household management has been tainted. The real Mrs Beeton was in fact a strip of a girl who could not cook.

The historian Kathryn Hughes has written the definitive biography of a woman born in 1836 who became a template for hardworking housewives.

Isabella Beeton was only 21 when she began cookery writing. Her first recipe for Victoria sponge was so inept that she left out the eggs. Seven years later she was dead.

How did she come to write the seminal book? “The answer is she copied everything,” Hughes said. It took Hughes five years to track down the recipes which she discovered had been brazenly copied by Mrs Beeton, almost word for word, from books as far back as the Restoration.

But Hughes says we should not necessarily think badly of Mrs Beeton. “Although she was a plagiarist, she was adding value. She was an extraordinary innovator.” Mrs Beeton had the radical idea of putting the ingredients at the start of the recipe. She also came up with the thought that it might be a good idea to write how long something should be cooked for…