Theresa May is putting children's health at risk by axing free school lunches for infant pupils, Nick Clegg has argued.
The former deputy prime minister said the plans outlined in the Conservative Party's manifesto to replace lunches with free breakfasts for all English primary school pupils was "cynical" and would offer just 7p's worth of food per child.
The Liberal Democrats claimed up to 250,000 children living in poverty across England will lose their free lunches as a result of the Tory plan.
During his time in government, Mr Clegg championed the free school meal policy, which meant all pupils in reception, year one and year two got a free hot lunch daily, regardless of the earnings of their parents or guardians.
Although free school meals will still be available to children from low-income families throughout their years in primary and secondary education, the Lib Dems highlighted analysis suggesting a poor take-up of the offer.
The party said the Children's Society charity estimated that half of all school aged children living in poverty - some 1.2 million - were not accessing free school meals as a result of a combination of an eligibility criteria that punished low-income, working families and the stigma associated with claiming them.
Based on these estimates, the Liberal Democrats calculated that a quarter of a million children living in poverty will no longer claim a free hot lunch at school - including 260 children living in the Prime Minister's constituency of Maidenhead - if the Tories are returned to power at the General Election.
The Lib Dems also calculated that under the Conservatives' costings of 7p per child per breakfast, each pupil could expect to tuck into either half a boiled egg, one slice of bread with 12 baked beans or 37.5 cornflakes and 100ml of semi-skimmed milk.
The Tories have acknowledged that the pledge to offer all primary school children a free breakfast could cost more than £60 million earmarked for it.
The price could escalate if many more youngsters than expected take up the offer, although the Conservatives belive take-up will remain similar to previous trials.
Mr Clegg said: "Theresa May's cruel and illogical decision to take away free, hot lunches for all infants will hurt hundreds of thousands of Britain's poorest children.
"It's clear that the reintroduction of means-testing for school lunches will mean many children losing out on what could be the only hot, nutritious meal that they receive each day.
"Theresa May is not only risking the health of some of our youngest children, but she will also create terrible inequality in the classroom.
"The Conservatives' cynical promise of a free breakfast is clearly not designed to reach all children because they have set aside a meagre 7p per breakfast per child. That's the price of half a boiled egg or just one slice of bread with 12 baked beans.
"Theresa May insists she wants to govern for everyone. But her regressive cutting of free school lunches is clear evidence she is prepared to ignore some of the poorest and most vulnerable children in our society.
"Just because the youngest don't vote, it doesn't mean that Theresa May should simply cast them aside."