DEFCON 3: Increase in force readiness above that required for normal readiness.DEFCON 4: Increased intelligence watch and strengthened security measures.DEFCON 5: Lowest state of readiness - this is the normal state of readiness in peacetime.Other countries have their own status levels, in some cases where this trope is played straight, in others they use phrases or colours instead. Thus, there is currently no real UK equivalent. However, these levels do not correspond to US Defcon levels - for example, the UK reached a 'critical' Threat Level in 20. The current system, dubbed the UK Threat Levels, doesn't use numbers at all, instead ranking the current likelihood of attack on a scale from Low to Critical (its most recent predecessor, the now-defunct BIKINI scale, used colours).

The UK did once operate a 'Queen's Order' level which escalated from 1 to 5, QO1 being the peacetime default and QO5 meaning (at the time) that the V-bombers had started their one way trip to enemy territory. The highest that the worldwide DEFCON level has ever risen to is 3. It's important to note that DEFCON levels can be limited to geographical regions, DEFCON 2 during the Cuban Missile Crisis and the Gulf War were limited to the affected regions. The Yom Kippur War of 1973 saw a brief period at DEFCON 3 (codename 'ROUND HOUSE', with some forces in the Middle East being at 2), as did 9/11. The highest state reached for the Strategic Air Command in US history was DEFCON 2 (codename 'FAST PACE', during the Cuban Missile Crisis), the Gulf War also led to forces in the Middle East reaching DEFCON 2, for obvious reasons - i.e., actually being at war. The use of nuclear weapons is authorized here, but they will still require unlock codes from high authority. DEFCON 1 (codename 'COCKED PISTOL') is the highest, referring to a confirmed state of nuclear war.

DEFCON 5 (codename 'FADE OUT' note These codenames are used during exercises to avoid confusion with the real deal) is the lowest state of alert, aka completely tranquil peace time. This is incorrect, and this trope is about the misuse of these terms.

In some movies, the phrase 'Defcon 5' or Defense Readiness Condition 5 is used to refer to the highest state of alert for the United States Armed Forces.

What defcon level are we in now