By Alex Stevenson Follow @alex__stevenson
Ed Miliband has hit upon an improbable chink in David Cameron's political armour: the chocolate orange.
The Labour leader pointed to the prime minister's failure to "sort out the chocolate orange" as proof that Mr Cameron's approach to capitalism was letting the country down.
Mr Cameron had pointed to WH Smith's practice of discounting chocolate oranges in 2006 as part of an effort to "stand up to big business", which also saw him attack BHS for selling sexy underwear to eight-year-olds.
"Look, if he can't sort out the chocolate orange, he's not going to be sort out the train companies, the energy companies, the banks, is he?" Mr Miliband told House magazine.
"I think it's very interesting that David Cameron's example of responsible capitalism was the chocolate orange.
"He's failed to sort it out, why? Because of his basic set of beliefs.
"You know he believes in a nudge philosophy which seems to amount to just asking people to do nice things. But that isn't going to sort out the problem. You've got to change the rules."
Mr Miliband attacked predatory capitalism in his party conference speech last autumn. The move prompted raised eyebrows from many in Westminster and provoked scorn from Conservatives.
But after Mr Cameron used a speech earlier this month to call for more "responsible capitalism", the leader of the opposition claimed he was winning the "battle of ideas".
"The issue for an opposition at this stage of a parliament is 'are you doing the right things'?" he asked.
"Are you facing up to the challenges which your party faces, which I think we are, on the issue of fiscal responsibility and issues like welfare and taking on the vested interests? Are you a party that people are coming towards?
"The race is probably one third run. Let’s see where we are at the end of the race."