The Conservative leader, who has called the police the “last great unreformed public service”, wants to end the restrictive practices that make it difficult to dispense with the services of bad officers.

He also wants to give policemen the right to retire with dignity before their 30 years’ service is up if, because of ill health, they are no longer capable of working to the required standard. They should be given the right to carry their pensions on to other employment.

He will also pledge that directly elected commissioners will replace the current system of police authorities.

During the Tory leadership campaign Mr Cameron said that politicians should not treat the police with kid gloves “just because police officers do such a brave job in protecting us”. One of his surprise appointments was to create a police reform spokesman, a job filled by Nick Herbert.

Today’s policy announcements will be made at an event hosted by Crime Concern.

Last night Mr Cameron said the changes he was making to his party were essential. He told The Sun: “If you don’t keep moving forward and addressing the challenges of tomorrow, you are not relevant. Politics is about making changes.

“Tesco wouldn’t be the business it is if it didn’t make radical changes to become a great business. Look at one of the great entrepreneurial brands, Virgin. It is always seeking fresh challenges. Sir Richard Branson doesn’t just do one thing and stop. He deliberately goes into difficult areas like trains.”

In the leadership election Mr Cameron said there were two central problems with policing. A lack of accountability prevented the public from telling the police what it wanted; and an organisational problem prevented the police giving the public what it wanted. “We need to make the police accountable to the people they serve. We should scrap the National Policing Plan and its associated targets and bureaucracy. And we should replace it with real local accountability. People should be able to hold a single individual to account for the performance of their local police force, and to vote that person in or out of office.

“There are restrictive practices that prevent police forces from delivering the kind of policing people want. We should be more aggressive in breaking down the barriers in the way of a professional, 21st-century police force, whether it’s political correctness from above, or ploddishness from below.”

Mr Cameron indicated last night that his programme of change has been ruffling feathers among traditional Tories, such as his own father. He added: “If you’re going to change things, that’s part of life. The challenge for politicians of my generation is to ask what are the big challenges now and what the Conservatives ought to be doing about it. We must show this is a decent, reasonable, moderate group of people with the right ideas.”

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