Proposals for experienced leaders to be able to enter the police service as superintendents were branded a “costly excess that ultimately will not bring any significant benefits” by police chiefs today.
The Government plans to launch a consultation on bringing in direct entry to the police service this autumn following recommendations in a major review of police pay and conditions, Home Secretary said.
But Derek Barnett, president of the Police Superintendents' Association of England and Wales (PSAEW), said the move would cost hundreds of thousands of pounds and bring an "operational risk".
"It's a costly excess that ultimately will not bring any significant benefits," Mr Barnett said.
But Mrs May told the PSAEW annual conference: "I believe it will bring a greater diversity of backgrounds to forces.
"It's not just about more women police leaders or more senior officers from ethnic minorities.
"It's about those who have gained broader experience and new perspective in fields like the wider public sector and business."
Mr Barnett added that, of the 43 forces in England and Wales, he thought only the Metropolitan Police might have the capacity to cope with implementing direct entry.
Earlier, he warned that the Government risked losing the goodwill of officers, who feel under attack with budget cuts and some of the most wide-ranging police reforms in more than 30 years.
"We cannot close our eyes to the situation we face," he said.
"This is how many feel, and the consequence which we are seeing already is the loss of goodwill.
"The same goodwill where police officers are recalled to duty and work additional long hours often without claiming reward, readily accept last-minute changes to shifts to fill the gaps on the street, cancelled leave and days off.
"The precise value of this goodwill is inestimable, but runs into hundreds of millions of pounds each year.
"If we lose the tradition of goodwill built up over many years it will be hard to recover it."
Mr Barnett warned there was a situation developing "where there is an erosion of the relationship between the service and the Government".
But he added it was "time to move on, cast off that cloak of victimhood and stop looking back".
He also urged officers of all ranks to unite, pointing to the murder of off-duty Pc Ian Dibell, 41, who was killed near his home in Clacton, Essex, while intervening in a row on July 9.
"This is not the time for the service to divide and become introspective," he said.
"Ian was murdered not because he held the rank of constable, he was off-duty.
"What happened to Ian could have happened to any police officer, regardless of rank.
"But what unites us is that each and every one of us, from chief constable to the newest recruit, holds the noble office of constable."
After hearing Mrs May's speech, he added that there was "a sense from it that there is an acknowledgement that there is time to change" the relationship.
Mrs May told the conference: "We may not always agree, but I want to listen to what you and your officers have to say and I want you to feel you have a stake in the future, because you have."