The new government has already announced 6.25 billion pounds of cuts in the current 2010/11 budget, but the cuts that will be announced in autumn as a result of the spending review set in motion by Osborne will be far larger, and are likely to draw fierce criticism and opposition.
Reaction from the trades unions to Osborne's announcement on Tuesday was immediate.
Brendan Barber, general secretary of the Trades Union Congress, said: "The Coalition seems to wants to go much further than the election talk of efficiency savings and cuts in intrusive state activities such as ID cards.
"We will welcome the offer to engage but will press hard against cuts that threaten higher unemployment or the services on which millions of ordinary people depend."