It was established following the terrorist attacks of 11 September 2001, on the initiative of the European Police Chiefs Task Force (EPCTF).
[1][2] Together, these top-tier units maintain a constant state of readiness, poised to respond to any security crisis in Europe at any time.
It was later formalised by a decision of the Council of the European Union in 2008, which also expanded ATLAS's functions to include the provision of assistance upon request to another Member State.
[1][2][4] In 2018, an ATLAS Support Office was established within Europol's European Counter Terrorism Centre (ECTC) in The Hague, Netherlands, thereby strengthening the role of the ATLAS Network within European law enforcement organisations.
[5] ATLAS uses the terms 'special intervention unit' and 'crisis situation' defined as follows: ATLAS recognises that a Member State may not have the means, resources, or expertise to handle all crisis situations, particularly large crises.