The Metropolitan Police must "move with the times" to save £800m over the next four years, Commissioner Sir Paul Stephenson has said.
It was "crazy" to own many buildings which "we do not fully use", he added.
And while he was "deeply concerned" about having to make cuts to Scotland Yard's budget, he said it was vital to be "doing better for less".
The force's budget is about £3.6bn, almost a third of the annual total for police across England and Wales.
Sir Paul said savings of £36m were planned in training by April 2014, along with £15m on catering and a further £7m on transport.
Cuts of £39m on property were also to be made, he added, with the possibility that some police buildings may be moved to industrial estates to reduce costs.
"We have got a huge estate here in London of buildings, some of which we do not fully use.
"That is crazy. It is bad planning and we have got to do something about that.
"There is a real reason to do something about this."
He said that although he was worried about making such large-scale savings, he lived "in the real world".
"Everybody is talking about doing more for less.
"I am talking about doing better for less."