Police in England and Wales will be told they must respond to emergency calls within 15 minutes in cities as part of new plans being announced on Monday.
Police officers must arrive at crime scenes in under 15 minutes in urban areas, and 20 minutes in the countryside when responding to serious crimes.
The new time restrictions will apply if there is a danger to life, an immediate threat of violence, the possibility of a serious injury or damage to property, or if a crime is in progress.
Home Secretary Shabana Mahmood is expected to announce a series of changes that have been billed as the biggest overhaul of policing in two centuries.
The Home Office said that under the new package, forces with slow response times would have senior officers from faster forces deployed to consult on improvements.
Ms Mahmood said: “People are reporting crimes and then waiting hours or even days for a response. By the time the police arrive, the perpetrators and witnesses are long gone.
“I will restore neighbourhood policing and scale up patrols in communities to catch criminals and cut crime.”
Ms Mahmood also said she will cut “red tape” and “unnecessary admin” preventing officers from spending more time on the streets.
The government will increase visible policing and patrols in communities, marking an extension of its neighbourhood policing guarantee.
Ms Mahmood also aims to reduce the number of police forces, deploy local forces to deal with smaller crimes such as shoplifting, and increase the power of home secretaries to sack chief constables.
Other measures to be introduced include introducing an FBI-style National Police Service to lead on terrorism, fraud and organised crime.
These changes came as part of a white paper entitled: “From local to national: a new model for policing”.
