Treasury Chief Secretary Danny Alexander has again slapped down calls for welfare to bear more of the burden of the coalition's austerity cuts.
The Liberal Democrat insisted there was no chance that benefits could be included in fraught negotiations over the 2015-16 spending review.
The intervention came amid pressure from Defence Secretary Philip Hammond and Home Secretary Theresa May for their departments to be shielded from a fresh round of curbs.
But Alexander told the Daily Telegraph that only the NHS, schools and international development would be exempt.
"I have been very clear and this is the collective view of the Government, that we took decisions on welfare in the autumn statement, and that the spending round is coming from departmental expenditure," he said.
"Every department around the table with the exception of those areas that are protected will have to make a contribution to that process. And, I'll spend most of my time working out with colleagues the best way to do that."
Alexander said he was not angry about ministers making public demands over the spending negotiations - due to be finalised by June - but stressed that their protests would make no difference.
"It has no effect on the decisions I will make, or the view that I will take on the right balance. The idea that having a great public campaign will influence the outcome, that's just wrong," he said.
Alexander said there was a case for looking in the future at whether universal benefits such as the winter fuel allowance should go to the wealthiest pensioners.
He also also strongly defended the Government's plans for childcare subsidies, arguing that it was beneficial for the economy for mothers to return to the workplace.
He said the current system was preventing this - and rejected suggestions that some women were forced to work because of the lack of support for stay-at-home mums.
"I want people who have had children, who want to go back into the labour market, to be able to do so. I do not want high child care costs to be the thing that prevents people contributing to the economy," he said.
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