The term police originates from the Greek word “Politeia, “ which means protection, order and social organisation. The term police was applied to all administrative activity, so from the perspective of Administrative Law, some experts define it as: “that activity that the Public Administration deploys in the exercise of its powers which, in order to guarantee the maintenance of public order, limits the rights of the administered employing the exercise, where appropriate, of coercion over them”. From which the following characteristics can be extracted:

• an activity carried out by the public administration and not by other public authorities;
• carried out in the exercise of its own powers, being an activity of public law.
• its purpose is to maintain public order;
• it is exercised through the limitation of the rights of the administered parties. Limitations are placed on the exercise of the right;
• employing the exercise of coercion, which distinguishes such an activity from the funds of promotional action and public service.

The notion in the liberal state, according to some scholars, of this activity is that public order is limited to ensuring “the tranquillity of the street”, and the administrative police is simply security police. Public order will comprise tranquillity, security and public health.

The notion in the current interventionist state. The administration is legitimised to coercively limit private individuals’ activities, not only for reasons of public order but for reasons of a broader concept, such as the public interest.

Since the 19th century, the generalised concept of police has been applied to the officials in charge of law and order; thus, we can find definitions of the police as: “the legitimised institution of social control whose mission is to guarantee peace and security in a community by imposing, if necessary, the observance of the laws by force”.

The origin of the police as a public service can be dated back to antiquity since, in one way or another, all societies have tried to have a public security service before the police model, although linked to the army (Egypt, Mesopotamia, Greece, Rome, Feudal Lordships, etc.) or the neighbours. The turning point and the creation of real police forces came after the French Revolution, when professional police forces emerged, made up of large units of hierarchical and disciplined men who, under the direction of a single chief, dedicated themselves exclusively to the active and permanent surveillance of the entire territory under the jurisdiction of the authorities on which they depended. However, this embryo of today’s police was eminently repressive since, in addition to being created along the lines of the army, they followed the political doctrine of the authorities, watching over the people and arresting those elements that could destabilise the existing social equilibrium. A key step was the birth in the 19th century of the London Metropolitan Police and the figure of the British policeman, who are called bobby’s because the creation of the force was carried out by Sir Robert Peel, who also laid the foundations of what a police force should be through nine principles that are still in force nowadays:

• the basic mission for which the police exist is to prevent crime and disorder;
• the ability of the police to perform their functions depends on public approval of their actions;
• the police must get the public to cooperate spontaneously in voluntary law enforcement in order to be able to achieve and maintain their respect;
• the degree of public co-operation that can be achieved diminishes in proportion to the need for the use of physical force;
• the police do not achieve and retain public favour by satisfying public opinion but by constantly demonstrating their absolute impartiality in the service of the law;
• the police use physical force to the extent necessary to secure the observance of the law or to restore order only when the exercise of persuasion, advice and warning has proved insufficient;
• the police, at all times, must maintain a relationship with the public which gives reality to the historic tradition that the police are the public and the public are the police; only the police who are paid to give full attention to the duties incumbent on every citizen in the interest of the welfare and existence of the community become members of the public;
• the police must always direct their actions strictly towards their functions and never pretend to usurp judicial power;
• the test of police efficiency is the absence of crime and disorder, not the visible evidence of police actions in dealing with it.

However, the key moment for understanding the current police forces did not occur until after World War II, when the police, in addition to the facet of being a “governmental” police force, became a public service of attention to the citizens and acted following the law and fundamental rights. Since then, an attempt has been made to bring the police closer to the society they protect and for them to collaborate with them, in what is known as community policing, or adopted in some European countries as proximity or neighbourhood policing, where police officers know their area of work and their neighbours know them, trying to prevent problems in their area by getting involved in them and finding solutions to them as far as they are able.