2017 was an important year in countering Salafi-jihadi terrorism. Midway through the year, the so-called caliphate collapsed as the Islamic State of Iraq and Syria (ISIS, also known as the Islamic State of Iraq and the Levant or Daesh) lost its hold on Mosul, Raqqa and other territory.

The sense of relief and joy didn’t last very long, as the ideas of Daesh and its progenitor, al-Qaeda, (AQ)—the group established by Osama bin Laden in the late 1980s, now led by Ayman al-Zawahiri and Osama’s son, Hamza bin Laden—persist and evolve.

History teaches that terrorists innovate in their tactics, strategy and organisation. They must do so to survive, as most nation-states are committed to the eradication of terrorism. Nevertheless, for each successful terrorist attack there have been many that the security services have foiled.