thumb|Multiple WB1400 Carrier Control Points on display at [[Hack Green Secret Nuclear Bunker. A WB1800 Operating Unit is visible in the right foreground.]]
thumb|WB1401 Speech Receiver with matching loudspeaker unit.
Handel was the code-name for the United Kingdom's national attack warning system in the Cold War that was in place between 1962 and 1992. It consisted of two injection sites (RAF High Wycombe and the Royal Observer Corps Group 21 bunker in Goosnargh, Lancashire) linked to a series of two hundred and fifty-two carrier control points installed in major police stations; in turn, the control points were linked to several thousand receiver units installed at "warning points" in various police, fire, and coastguard stations, government buildings, hospitals, industrial centres, and Royal Observer Corps posts,
A Handel warning console can be seen at the Imperial War Museum in London among their Cold War exhibits, to an EMP-resistant equipment line falling under the WB1400 series of designations. WB1400-series receivers were also trickle-charged to ensure that they would work when needed (while earlier receivers often suffered from unnecessary battery drainage due to being erroneously left on outside of test periods). The "operating unit" console at the injection sites was known as the WB1800.
Warning messages
{| class="wikitable sortable"
|-
! Message
! How it is received
! Action to be taken
! Notes
|-
| Test broadcast (War emergency)
| The words "Test call, testing" (said three times) followed by the message: "A test of the Attack Warning signal will now follow" (also said three times). This would be followed by various signals and then the message: "A test of the Attack Warning signal has just been made" (said twice).
| None
| If an attack warning occurred during the test, the latter was to be abandoned immediately.
|-
| Attack warning
| Warbling note followed by the message: "Attack warning RED!" This would be followed by a minute-long or sound siren producing one long note but interrupted in short succession. Could also be given by church bells or word of mouth from the police and civil defence wardens
| Fell out of use by the late 1960s.
|-
| All clear
| High-pitched pip signal followed by a spoken message: "Attack message WHITE!"