Labour has accused the prime minister of being "out of touch," after he admitted not knowing the price of a supermarket loaf of bread – because he bakes his own.
Interviewed on radio, he guessed that a budget loaf would cost more than £1, only to be told it was 47p.
Describing how he makes bread at his Oxfordshire home, he said: "You set the timer overnight so when you wake up there is this wonderful smell wafting through your kitchen."
It came after Mayor of London Boris Johnson admitted he didn't know the cost of a pint of milk.
He told Newsnight's Jeremy Paxman it was "about 80p or something like that".
Told it was half that, he conceded: "Well, there you go, I don't know how much a pint of milk costs. So what?"
Mr Cameron defended his ignorance of the price of supermarket bread by saying he prefers to bake his children healthy homemade granary loaves made with local flour.
The Prime Minister guessed that a value sliced white loaf would cost "well north of a pound" when he was quizzed about the cost of living on LBC 97.3 Radio.
Told by presenter Nick Ferrari that the true cost was around 47p, he revealed that he prefers to use an electric breadmaker – and even plugged the manufacturer of the one he uses.
"I don't buy the value sliced loaf, I've got a breadmaker at home which I delight in using and it turns out in all sorts of different ways," he said.
"But you can buy a loaf in the supermarket for well north of a pound."
Told the true price, he added: "I don't buy the... look I'm trying to get my children to eat the granary – and they take it actually, they like my homemade bread."
Labour vice-chair Michael Dugher said: "David Cameron is so out of touch he's almost a parody of himself.
"Ordinary families are worse off thanks to the cost of living crisis under his Government, with prices rising faster than wages in 38 of the 39 months he has been in Downing Street.
"It comes as no surprise that he doesn't buy a value loaf of bread. The only surprise is when he said 'I have a breadmaker' – most people will have assumed he had his own personal baker, rather than a machine."