Traditionally, acts of terrorism were executed by organisations that identify, train, plan and deploy individuals or groups to carry out these acts.

This is partly because the skills needed for such operations do not reside in any one individual and, hence, the need for a team comprising individuals with different types of expertise and experience.

Terrorist organisations have mutated in response to the effectiveness of counter-terrorism operations.

Prior to now, they recruited ethnic and religious minorities of a fundamentalist disposition and transported them to bases in different parts of the world to be indoctrinated to the point at which they are willing to sacrifice their lives for the cause.

They would then infiltrate the target country to carry out a specific operation, or to be sleeper cells awaiting deployment at some future date. The structure and operation of global terrorism was designed and managed from a central leadership and planning centre, usually outside the target countries.

Because terrorism was directed by organisations, it was possible to infiltrate their membership and structures and to gather intelligence on their operations by a range of sophisticated electronic surveillance.

The United States and, to a lesser extent, other countries have been able to monitor terrorist organisations, terminate some of their leaders and prevent some of their operations.

The efficacy of this type of counter-terrorism strategy is now made outdated by a significant change in the tactics of terrorist organisations which are now shifting from acts executed by small groups to freelance acts carried out by individuals or by a team of two, such as the bombing of the Boston Marathon.

These persons exist in sleeper cells and take the initiative based on general directions and not specific instructions about targets and dates. The technology of killing and the Internet have unwittingly assisted in facilitating the individualisation of terrorism.

This is characterised by terrorists who are natives and citizens of the target country taking the initiative based on a general directive to take action. The details of what, how and when they perpetuate terrorist acts are known only to them. This makes it extremely difficult to identify who is a terrorist or who will become a terrorist. It means that anyone could be a terrorist.

The implication is that surveillance has to cover every citizen and that is simply not possible a la George Orwell’s dystopian novel Nineteen eighty-four.

The most difficult cases to intercept are those in which an individual unconnected to any terrorist organisation acts alone. For example, the most devastating act of terrorism in the US prior to the 9/11 attack was by a domestic terrorist, 21-year-old Timothy McVeigh, who detonated a truck bomb in front of the Alfred P Murrah Federal Building in Oklahoma City on April 19, 1995, killing 168 people and injuring over 600.

This White American citizen and former US soldier acted alone, had no non-US affiliations and was not trained by any known terrorist organisation.

The two brothers accused to have carried out the deadly attack on French satirical magazine Charlie Hebdo fit the profile of individual terrorists. It was virtually impossible to anticipate and detect.

This is an ominous new development, making it harder to fight terrorism, because the next terrorist could be your neighbour or co-worker.