Threat level is a term used by governments to indicate the state of preparedness required by government servants with regard to threats to the state:

Current

UK Threat Levels The United Kingdom Terror Threat Levels, often referred to as UK Threat Levels, are the alert states that have been in use since 1 August 2006 by the British government to warn of forms of terrorist activity. In September 2010 the threat level ...

, the system used by the United Kingdom since 2006 *

National Terrorism Advisory System The National Terrorism Advisory System (NTAS) is a terrorism threat advisory scale used by the US Department of Homeland Security since April 26, 2011. The NTAS is the replacement for the often-criticized, color-coded Homeland Security Advisor ...

, the system used by the United States since 2011

Former

BIKINI state The Bikini state was an alert state indicator previously used by the UK Ministry of Defence to warn of non-specific forms of threat, including civil disorder, terrorism or war. Signs giving the current alert state were displayed at the entrance ...

, the system used by the United Kingdom 1970–2006 *

Homeland Security Advisory System In the United States, the Homeland Security Advisory System (HSAS) was a color-coded terrorism threat advisory scale created in March 2002 under the Bush Administration in response to the September 11 attacks. The different levels triggered spe ...

, the system used by the United States 2002–2011 {{disambiguation