David Cameron's benefit cuts have been savaged by 27 bishops, who say they have caused a "national crisis".
The Church of England leaders directly link welfare changes to the rise of foodbanks, saying the measures were making people go hungry and driving them into poverty.
In an open letter to the Mirror to mark the start of Lent on March 5, they tell the Prime Minister - who yesterday said it was his "moral mission" to make the changes - that he has an “acute moral imperative to act.”
"Half a million people have visited food banks in the UK since last Easter and 5,500 people were admitted to hospital in the UK for malnutrition last year", they wrote.
"We often hear talk of hard choices. Surely few can be harder than that faced by the tens of thousands of older people who must 'heat or eat' each winter, harder than those faced by families whose wages have stayed flat while food prices have gone up 30% in just five years.
"Yet beyond even this we must, as a society, face up to the fact that over half of people using food banks have been put in that situation by cut backs to and failures in the benefit system, whether it be payment delays or punitive sanctions."
They added: "We call on government to do its part: acting to investigate food markets that are failing, to make sure that work pays, and to ensure that the welfare system provides a robust last line of defence against hunger."
Their intervention comes just days after Britain's top Catholic, Vincent Nichols, attacked the government's welfare changes, saying the number of people turning to foodbanks was a "disgrace".