Liberal Democrat leader Nick Clegg has become engaged in a war of words with controversial baby author Gina Ford.
The father-of-three described her methods as "absolute nonsense".
Ford has sold millions of copies of "The Contented Little Baby Book" but her advice divides parents.
Clegg told the Sunday Times it was like "following a sort of Ikea assembly... manual".
But Ford has hit back at Clegg, saying he had "insulted the parenting choice of more than two million British voters".
She said: "What is sad about this statement is that it comes from a supposedly intelligent man who would have us believe that he is capable of running Great Britain."
Ford clearly isn't one to be messed with - she has previously launched a libel case against the Mumsnet website over comments published. So be careful what you say...
Clegg was talking about Ford after he told the interviewer he had been up four times the night before with his youngest child, 10-month-old Miguel.
The interviewer asked if he would consider using Ford's methods.
"Don't get me on to Gina Ford," he said. He said he and his wife Miriam had tried to use her book with their first child but the instructions were "absolute nonsense".
"I will never forget - in the middle of the night, Antonio woke up," he said. "Miriam said to me: What does the book say? I remember saying to her: 'Okay, we have got to stop this. I have subcontracted my parental instincts to this book'."
Later Mr Clegg's spokeswoman told the BBC that he had been expressing a personal opinion and his remarks were simply those of a "passionate father who like many parents feels acutely the effect of his children's sleeping pattern on his own life" and were not intended "in any way personally against Ms Ford".
I've never followed the advice of Gina Ford - it sounds like it would go against my instincts. But then my daughter doesn't sleep, so who knows?
Have you tried Gina Ford's methods? Did they work for you?
Source: BBC