The Home Secretary has sparked anger from police chiefs after she accused them of ignoring orders to cut through red tape.
Theresa May said she was frustrated forces were failing to join her drive to free up more time for crime fighting.
Senior officers said Mrs May was being unfair as they claimed reducing bureaucracy was not as simple as "flicking a switch".
Mrs May, launching a staunch defence of her wide-ranging police reforms, told chiefs "you can see we really mean business".
"But here's the problem - not all of you are following my lead," Mrs May told a conference in Harrogate.
"Some of you are still setting your forces targets that we've scrapped nationally."
Sir Hugh Orde, president of the Association of Chief Police Officers (Acpo), told Mrs May there was "some lack of clarity" over her reforms, and that she was risking public safety.
But Mrs May responded by saying: "Sir Hugh, police reform should be a cause for optimism for police chiefs, not fear."
Mrs May said she was ordering every organisation across the criminal justice system to stop wasting police time.
"All of this work is aimed at freeing your officers to fight crime," she added.