Ed Miliband has been accused of being out of touch after under-estimating the cost of his family's weekly food shop.
The Labour leader said the supermarket bill came to around £70 or £80 but later insisted that he was referring only to the amount spent on "basic" groceries such as fruit and vegetables.
Critics were quick to seize on the comments as proof he did not know the details of his household bills and instead "took a punt".
Mr Miliband made the initial estimate after being pressed about his food spending when he was talking about Labour's plans to tackle the cost-of-living crisis on ITV's Good Morning Britain.
He said: "We probably spend £70, £80 a week on groceries at least, probably more than that. The point is that different families will have different costs that they face but what I am clear about is that there is a crisis facing so many people."
Mr Miliband was told that the average weekly bill for a family of four is more than £100 – so he would be spending "significantly more" than £70 to £80.
"Lots of people are facing a real struggle," he replied. "I am relatively comfortably off, but what I know is that there are deep issues that need to be tackled and we are determined to tackle them."
He later admitted that his shopping estimate may have been on the low side, saying he had been thinking of the bill for "basic groceries".
"Well, I said this morning it was on the basic groceries, the basic fruit and vegetables, about £70 or £80 – the total shopping bill was slightly higher than that, obviously," he told the BBC.
"On the basics, I was saying it was about £70 or £80 but the overall shopping bill would obviously be higher."
Figures from the Department for Environment, Food and Rural Affairs Family Food survey show the average weekly expenditure on all household food and drinks in 2012 was £29.29 per person, an increase of 4.6% on 2011. Total expenditure on household food and non-alcoholic drink rose by 4.3% to £25.98 per person and was 8.9% higher than in 2009.
Figures from the Office for National Statistics showed the average weekly expenditure for a household with two adults and two children on food and non-alcoholic drinks in 2012 in the UK was £83.60.
The Labour leader's comments sparked robust exchanges on the Mumsnet website.
TheWordFactory wrote: "Basically, he doesn't know! He took a punt and made himself look daft. I suspect he hasn't stepped a foot in Tesco since 1982."
Contributor bleedingheart wrote: "It is so ridiculous to try and perpetuate this 'man of the people' nonsense. Of course politicians need to be aware of the struggles people face and work on the solutions but I don't for a second think Miliband does his own shopping or Cameron for that matter."