A police officer (also known as a "policeman", Police Constable, and colloquially as "copper", "cop" or "bobby") is a warranted worker of a police force.

As well as general policing, officers can be trained in special duties such as counter-terrorism; surveillance; child protection; royalty or diplomatic protection; and investigating major crime such as fraud, rape, murder, and people or drug trafficking.

It must be noted that the responsibilities of a police officer are extremely broad, although the most common, despite country, are often keeping the peace, enforcing the law, protecting the public and property, and the investigation of crimes. Officers are expected to be able to respond in some fashion to any and all situations that may arise while they are on duty. Also officers must act as government officials in the cases of investigation. In some communities, rules and procedures governing conduct and duties of police officers requires that they act if needed even when they are off duty, such as the United Kingdom, where police officers retain full powers of arrest while not on duty.^{[citation needed]}

In most Western legal systems, the major role of the police is to maintain order, keeping the peace through enforcement of laws and societal norms. They also function to discourage and investigate crimes, with particular emphasis on crime against people, property, or the law. In order to maintain public order, police have legal authority to apprehend suspected perpetrators, detain them, and then inform the appropriate authorities. See criminal law.

Police are often used as an emergency service and may provide a public safety function at large gatherings, as well as in emergencies, disasters, and search and rescue situations. To provide a prompt response in emergencies, the police often coordinate their operations with fire and emergency medical services. In some jurisdictions, individuals serve jointly as police officers as well as firefighters or paramedics. In many countries there is a common emergency service number that allows the police, firefighters, or medical services to be summoned to an emergency.

Police are also responsible for reporting minor offenses by issuing citations which typically may result in the imposition of fines, particularly for violations of traffic law. Traffic enforcement is often and effectively accomplished by police officers on motorcycles — called motor officers, these officers refer to the motorcycles they ride on duty as simply motors. Police are also trained to assist persons in distress, such motorists whose car has broken down and people experiencing a medical emergency. Police are typically trained in basic first aid such as CPR.

In addition, many park rangers are nowadays commissioned as law enforcement officers and carry out a law-enforcement role within national parks and other backcountry wilderness and recreational areas. Military police perform law enforcement functions within the military.

Police can serve as an instrument of oppression in jurisdictions where the political climate is hostile to plurality. Police forces have been used historically to suppress dissent and crush protests when political leaders had the authority to place such limits on freedom to assemble. Police brutality is a term generally applied to oppressive or violent actions by police officers in a jurisdiction where the citizens freedoms may have been violated by police overstepping their authority.

In socialist and anarchist theory and analysis, the police are seen as the main force responsible for defending the interests of the bourgeoisie and maintaining the status quo, primarily by protecting private property and capital from the "dispossessed" proletariat classes. Socialists and anarchists argue that although police may have in at least some cases the responsibility for maintaining the safety of citizens and even carry out such a responsibility, most crimes originate from class inequality or the psychological effects of this combined with hierarchy, and therefore that these crimes would not exist in a classless and non-hierarchical society, where goods are evenly distributed and hierarchy has been removed.

Under socialist theories of law, the law, and the state itself, are established to serve as a tool of the dominant class or classes of a society. In a Communist society, this has meant that law is intended to serve as a tool of the Communist party in promoting and protecting the revolution and overseeing the restructuring of society. In practice, this meant that police in Communist countries have had a role as secret police against political opponents and dissidents against the Party. This has presented a challenge for post-Communist societies trying to establish effective police institutions and the rule of law, as the vacuum following Party dominance and the memories of the activities of predecessors such as the NKVD, KGB, Stasi and Securitate left many post-Communist states without police forces widely considered legitimate or respectable.

In most countries, candidates for the police force must have completed some formal education. Increasing numbers of people are joining the police force who possess tertiary education and in response to this many police forces have developed a "fast-track" scheme whereby those with university degrees spend two to three years as a police constable before receiving promotion to higher ranks, such as sergeants or inspectors. (Officers who work within investigative divisions or plainclothes are not necessarily of a higher rank but merely have different duties.) Police officers are also recruited from those with experience in the military or security services. Most law enforcement agencies now have measurable physical fitness requirements for officers. In the United States state laws may codify state-wide qualification standards regarding age, education, criminal record, and training but in other places requirements are set by local police agencies.

Police agencies are usually semi-military in organization, so that with specified experience or training qualifications officers become eligible for promotion to a higher supervisory rank, such as sergeant. Promotion is not automatic and usually requires the candidate to pass some kind of examination, interview board or other selection procedure. Although promotion normally includes an increase in salary, it also brings with it an increase in responsibility and for most, an increase in administrative paperwork. Unlike military service, it is not unusual for police officers to remain or choose to remain at lower levels, never getting promoted. There is no stigma attached to this - experienced line patrol officers are highly regarded.

After completing a certain period of service, officers may also apply for specialist positions, such as detective, police dog handler, mounted police officer, motorcycle officer, water police officer, or firearms officer (in forces which are not routinely armed).

In some countries such as in Singapore, police ranks may also be beefed up through conscription, similar to national service in the military. Qualifications may thus be relaxed or enhanced depending on the target mix of conscripts. In Singapore, for example, conscripts face tougher physical requirements in areas such as eyesight, but are less stringent with minimum academic qualification requirements. Some police officers also join as volunteers, who again may do so via differing qualification requirements.

Due to the unpredictable nature of law enforcement, police officers can encounter many dangerous situations in the course of their career. Officers face an increased risk of infectious diseases, physical injury and death, as well as the potential for emotional disorder due to both the high stress and inherently adversarial nature of police work. These dangers are encountered in many different situations, such as the investigation, pursuit, and apprehension of criminals, motor vehicle stops, crimes, response to terrorism, intervention in domestic disputes, investigating traffic accidents, and directing traffic. The constant risk, uncertainty and tension inherent in law enforcement and the exposure to vast amounts of human suffering and violence can lead susceptible individuals to anxiety, depression, and alcoholism.^{[citation needed]}

Individuals are drawn to police work for many reasons. Among these often include a desire to protect the public and social order from criminals and danger; a desire to hold a position of respect and authority; a disdain for or antipathy towards criminals and rule breakers; the professional challenges of the work; the employment benefits that are provided with civil service jobs in many countries; the sense of camaraderie that often holds among police; or a family tradition of police work or civil service. An important task of the recruitment activity of police agencies in many countries is screening potential candidates to determine the fitness of their character and personality for the work, often through background investigations and consultation with a psychologist. Even though police work is very dangerous, police officers are still seen by most people as necessary to maintain order. As a result, police officers are generally held in high regard by the population they serve, although this can vary from country to country, depending on past experiences with the police or general national perception.

Line of duty deaths are deaths which occur while an officer is conducting his or her appointed duties. Despite the increased risk of being a victim of a homicide, automobile accidents are the most common cause of officer deaths. Officers are more likely to be involved in traffic accidents because of their large amount of time spent conducting vehicle patrols, as well as their work outside their vehicles alongside or on the roadway, or in dangerous pursuits. Officers killed by suspects make up a smaller proportion of deaths. In the U.S. in 2005, 156 line of duty deaths were recorded of which 44% were from assaults on officers, 35% vehicle related (only 3% during vehicular pursuits) and the rest from other causes: heart attacks during arrests/foot pursuits, diseases contracted from suspects, accidental gun discharges, falls, and drownings.^[1]

Police officers who die in the line of duty, especially those who die from the actions of suspects, are often given elaborate funerals, attended by large numbers of fellow officers. Their families may also be eligible for special pensions. Fallen officers are often remembered in public memorials such as the U.S.'s National Law Enforcement Officers Memorial.

Statistically, 18,838 law enforcement officers are known to have died in the line of duty in the United States. In Canada, 757 law enforcement officers met a similar fate. In the United Kingdom, about 3,600 law enforcement officers are known to have died in the line of duty. The Singapore Police Force registered just over 100 deaths in a century up to the year 2000.

A typical police officer, dependent on duties may carry various equipment on their duty belt, to assist them in performing their duties

The equipment carried typically includes some or all of the following (varies from country to country):

• Helmet or flat cap
• Handgun
• Spare ammunition
• Body armor
• Radio or communications equipment and PDA.
• Night stick, truncheon or baton.
• Restraints: handcuffs or Plasticuffs
• Notebook for recording incident information, taking down statements, etc
• Pencil or pen
• Pepper spray, PAVA Spray or CS gas
• Sidearm and tasers (in jurisdictions where police are armed)
• Badge, warrant card or ID
• Evidence bags
• Flashlights
• Hi-visibility jacket or vest (doubles as a waterproof garment)
• latex gloves

Vehicle-based officers may also typically carry additional equipment, as would those assigned to specialist units.

Equipment carried on patrol vehicles might typically include:

• Barrier/hazard tape
• Industrial rubber gloves
• Traffic cones
• Loud hailer
• First aid kit
• Breath alcohol meter
• Speed gun
• Video recording equipment
• Chalk, sand or spray paint
• Rope or chain
• Hi-powered lamps, torch, flashlight
• Box-cutter
• Warning signs
• Shotguns and other weapons (in jurisdictions where the police are armed)

Police officers may patrol on foot, but most commonly have some form of transport.

• Police cars
• Police motorcycles or bicycles: used everywhere, but especially useful in congested urban areas
• Police horses: mounted police patrol parks, urban centers, and events such as parades
• Bicycles: useful in urban centers, school campuses, and parks

• Peace officer
• Military police
• Fictional police officers.
• Police brutality
• Cops (TV series)
• Police procedural
• President Grover Cleveland-former Sheriff of Erie County, New York
• President Theodore Roosevelt-Deputy Sheriff in Dakota territory and Police Commissioner of New York City.

• Metropolitan Police history
• http://www.newscotlandyard.police.uk/foi/pdfs/other_information/corporate/operational_uniform_and_equipment.pdf
• http://www.west-midlands.police.uk/publications/freedom-of-information/policy.asp?id=144
• http://www.gmp.police.uk/mainsite/pages/pcsouniform.htm,ts=2
• http://www.policelink.com