The Government saved £3.75 billion in less than a year by cutting jobs, axing projects and reining in spending.
Cabinet Office Minister Francis Maude said an "ambitious approach to saving money" had delivered the "staggering" results.
He insisted the cash had been clawed back from overhead costs, not services, and much more would be found over the coming year.
Officials now have to get his approval on a range of spending decisions, including any marketing proposals costing more than £20,000 and ICT projects upwards of £1 million.
Use of consultants has been greatly reduced, something Mr Maude said would be welcomed by civil servants.
"Civil servants were often frustrated when consultants were used, it was very dispiriting for them," he said.
Other money-saving examples include rejigging government office space to free up the equivalent of 70 Wembley football pitches, allowing major reductions in rent costs.
The e-Borders programme, aimed at electronically collecting information on people moving in and out of the UK, is one of the projects that has been dropped because it would "not deliver".
The cash savings, which have been independently audited, were made between May 2010 and March this year.
Last October Mr Maude pledged to leave "no stone unturned" in the hunt for savings at the centre of government, promising to deliver better for less to help divert funds towards addressing the deficit.