In any county of the first class having a charter form of government and having a population of at least nine hundred thousand inhabitants, each city, town, or village having a population of four hundred or more shall operate and maintain a police department on a twenty-four hour per day basis so that at least one police officer will always be on duty and available to respond to any call for assistance. The governing body of the city, town or village may contract with another city, town, village or the county for twenty-four hour per day police service. If the governing body of the county after notice to the city, town or village and after public hearing thereon, find that the city, town or village has not provided twenty-four hour per day police service with at least one police officer always on duty as a police officer, it shall direct the county to enter into a contract with the city, town or village to provide such service for the city, town or village.