Cuts in government spending and/or increases in taxes will be needed in order to bring down the budget deficit and reduce borrowing.
In the Budget the chancellor held back from announcing further details on where those spending cuts might come.
Both Labour and the Conservatives have said they will hold a spending review should they win the forthcoming election.
But Mr Darling did announce that government departments including the Department of Justice and the Department for Business Innovation and Skills would make savings through efficiency savings and the relocation of staff out of London.
The Conservatives are expected to unveil their plans for cuts before the election, while Labour has pledged to delay cuts until the economy has recovered more fully - a position backed by the Liberal Democrats.