Paul John, director of the Institute for Fiscal Studies, said the effects of further spending cuts on government departments already having their budgets slashed would be "hard to contemplate" and it was more likely that "protected" departments would be hit in the next parliament.
The effects of concentrating all those cuts on currently unprotected areas of public service spending look hard to contemplate.
A more likely scenario perhaps is that other choices will be made after the next election.
Taxes could rise, hitherto protected elements of public spending, like the NHS and pensions, could be hit, or the date at which we reach fiscal balance will be pushed further out.
More top news
Fine and dry with late sunshine this evening
EU parliament confirms Ursula von der Leyen has been elected as the first female European Commission president in a 383-327 vote.
Anna Soubry said Chuka Umunna refused demands to be leader of Change UK before leaving her pained by quitting the party without a call.