Top Tory Michael Gove has piled pressure on Liz Truss to extend free school meals provision to stop kids from going hungry.
The Conservative former Education Secretary said all primary pupils should get free school dinners "in an ideal world", in a major boost to the Mirror and NEU campaign to broaden the scheme.
As rising food and fuel bills push hard-pressed Brits to the brink, Mr Gove urged Liz Truss's Government to extend free school meals to all children in Universal Credit households right now.
This would provide targeted support to around 1.5million more children, according to estimates by the Children's Society.
Mr Gove said it was a "more than worthwhile intervention considering some of the other policy choice in front of us," in a swipe at the embattled Prime Minister.
TV chef Jamie Oliver hailed his comments, tweeting: "This is promising to hear.
"Right now 800,000 children living in poverty don’t have access to free school meals. This needs to change."
It comes as Ms Truss faces a fresh Tory revolt over plans to hit millions of poor Brits with a real terms benefits cut by scrapping a vow to uprate welfare in line with inflation.
The Mirror and the NEU are campaigning for free school meals for all children in primary schools in England. The devolved administrations in Scotland and Wales have already pledged to bring this in.
Currently, children in state schools in England get free school meals up to the end of Year 2 and then only if their families claim certain benefits.
Children whose families claim Universal Credit can only get school lunches if their household earns less than £7,400 a year after benefits.
Mr Gove told an Onward fringe event at Conservative conference: "Times are tight. In an ideal world, I think that we should have universal free school meals for all children in primary school. That would be my ideal.
"We have already extended it to infants, we should extend it further in an ideal world. Resources are tight, I don't want to be unrealistic, I don't think any of us do.
"But what we can do is we can extend free school meals to every child in a family in receipt of universal credit for £500million."
He went on: "£500million is big potatoes - no pun intended - but given the scale of the challenge we face and the benefits it brings, it seems to me that the wider debate that we are having about where extra pounds secure value, it seems to me this is a more than worthwhile intervention considering some of the other policy choices in front of us."
In a veiled swipe at the PM, Mr Gove said it was not "socialist" to intervene when people are struggling.
He told the audience: "Interventions by the state at critical moments in order to improve the welfare of all its citizens are not socialist... Conservatives care about communities, the national community, and they care about public health interventions."
Boris Johnson's former food tsar Henry Dimbleby said extending free school meals to Universal Credit households was a "no brainer" and argued that the case for universal provision was "very strong".
Mr Dimbleby accepted that the sugar and salt reformulation tax he proposed in his food strategy last year was "not doable" during the cost of living crisis but said action on free school meals was key.
He told the event: "The case for universal free school meals is I think very strong.
"There is good evidence to show it creates a culture in the school that actually has a benefit, not just on the performance of those who didn't get school meals but of those people already on school meals, because it gets everyone eating together."
He said the "relatively cheap" plan to extend it to Universal Credit households was a "no brainer".
Anna Taylor, executive director of The Food Foundation, welcomed the news, adding: "As a former Education Secretary he knows only too well the lifelong disadvantage suffered by children who do not receive a decent diet.
"It causes obesity and lifelong poor health, reduces their capacity to learn and limits their opportunities in the job market."
A Government spokesperson said: “We have expanded access to free school meals more than any other government in recent decades, which currently reach 1.9 million children. We are also investing up to £24m in our National School Breakfast Programme, which provides free breakfasts to children in schools in disadvantaged areas.
“The Chancellor has unveiled a new growth plan, taking decisive action to get households and businesses through this winter and the next, by growing the economy to raise living standards for everyone.”