Rainbow Code


The Rainbow Codes were a series of code names used to disguise the nature of various British military research projects. They were mainly used by the Ministry of Supply from the end of the Second World War until 1958, when the ministry was broken up and its functions distributed among the forces. The codes were replaced by an alphanumeric code system, consisting of two letters followed by three digits.

History

During World War II, British intelligence was able to glean details of new German technologies simply by considering their code names. For instance, when they heard of a new system known as Wotan, Reginald Victor Jones asked around and found that Wotan was a one-eyed god. Based on this, he guessed it was a radio navigation system using a single radio beam. This proved correct, and the Royal Air Force was able to quickly render it useless through jamming.
Wishing to avoid making this sort of mistake, the Ministry of Supply initiated a system that would be entirely random and deliberately unrelated to the program in any way, while still being easy to remember. Each rainbow code name was constructed from a randomly selected colour, plus an noun taken from a list, for example:
While most colour and noun combinations were meaningless, some combinations produced real names, although quite unrelated to the project they designated. For example, "Black Maria" is also a nickname for a police van and the "Red Duster" is a nickname for the Red Ensign, the flag flown by British merchant ships. Some code names were not assigned through the official system, but created to sound like it. The Blue Yeoman radar is an example, an unofficial name created by combining the names of two other projects, Blue Riband and Orange Yeoman.
The names were mostly dropped with the end of the Ministry in 1959. Its functions were split between the War Office, the Air Ministry, and the newly created Ministry of Aviation, which was responsible for civil aviation. After the reorganization, projects were mostly named with randomly selected codes comprising two letters and three digits, e.g. BL755, WE.177. Rainbow codes, or at least names that look like them without being official, have occasionally been used for some modern systems; current examples include the Orange Reaper electronic support measures system and the Blue Vixen radar—the latter most likely so named because it was a replacement for the Blue Fox radar.

Projects

Black

  • Black Arrow – satellite launch vehicle derived from Blue Streak/Black Knight
  • [|Black Knight] – launch vehicle used to test re-entry vehicles for [|Blue Streak]
  • Black Maria – fighter IFF interrogator
  • [|Black Prince] – proposed satellite launch vehicle based on Blue Streak/Black Knight – a.k.a. [|Blue Star]
  • Black Rock – surface-to-surface guided missile

    Blue

  • Blue Anchor – X-band CW target illumination radar for Bristol Bloodhound – a.k.a. AMES Type 86
  • Blue Badger – truck-mounted nuclear land mine – later renamed [|Violet Mist]
  • [|Blue Bishop] – portable 2.5 MW nuclear-powered electrical generator – previously [|Green Janet]
  • Blue Boar – TV-guided bomb
  • Blue Boy – VHF speech scrambling
  • [|Blue Bunny] – ten-kiloton nuclear mine; see [|Blue Peacock]
  • Blue Cat – nuclear warhead, a.k.a. Tony – UK version of US W44, a.k.a. Tsetse
  • Blue Cedar – AA No. 3 Mk. 7 mobile anti-aircraft radar
  • Blue Circle – joke name for cement ballast used in place of a radar in the Tornado F.2
  • Blue Danube – the first British nuclear weapon in service
  • Blue Devil – T4 optical bombsight – drift and ground speed from Green Satin
  • Blue Diamond – AA No. 7 anti-aircraft radar
  • Blue Diver – ARI 18075 airborne low-band VHF jammer – against metric frequency radar such as Tall King – fitted to Victor and Vulcan
  • Blue Dolphin – Blue Jay Mk V for Sea Vixen – see Hawker Siddeley Red Top
  • Blue Duck – anti-submarine warfare missile, entered service as Ikara
  • Blue Envoy – surface-to-air missile to OR.1140, replaced Green Sparker as "Stage 2" SAM
  • Blue Fox – kiloton-range nuclear weapon, later renamed Indigo Hammer – not to be confused with the later Blue Fox radar
  • Blue Fox – airborne radar
  • Blue Jacket – ARI 5880 airborne Doppler navigation radar fitted to Hawker-Siddeley Buccaneer aircraft
  • Blue Jay – air-to-air missile – entered service as de Havilland Firestreak
  • Blue Joker – balloon-borne early warning radar – possibly also known as AMES Type 87
  • Blue Kestrel – search radar
  • Blue Label – AMES Type 84 radar
  • Blue Lagoon – infra-red air-to-air detector
  • Blue Mercury – Centurion Crocodile flamethrower tank
  • Blue Moon – nuclear-armed cruise missile project, replaced by Blue Streak
  • Blue Oak – AWRE Atlas 2 super-computer used for simulation of nuclear explosions
  • Blue Orchid – Marconi doppler navigation equipment for helicopters
  • Blue Parrot – ARI 5930 I band automatic contour-following radar for Buccaneer – also known as AIRPASS II
  • Blue Peacock – ten-kiloton nuclear land mine – also known as Blue Bunny and [|Brown Bunny]; it used the Blue Danube physics package
  • Blue Perseus – flamethrower kit for the Centurion Crocodile tank
  • Blue Ranger – delivery of Blue Steel to Australia
  • Blue Rapier – Red Rapier – missiles – see UB.109T
  • Blue Riband – large jamming-resistant radar. Cancelled 1958 and replaced by a smaller version as Blue Yeoman
  • Blue Rosette – short-case nuclear weapon bomb casing for reconnaissance bomber to spec R156T, including the Avro 730, Handley Page HP.100, English Electric P10, Vickers SP4 and others
  • Blue Saga – ARI 18105 airborne radar warning receiver – fitted to Victor and Vulcan
  • Blue Sapphire – astro-navigation system – see also Orange Tartan
  • Blue Shadow – navigation equipment for Canberra B.16, developed as Yellow Aster
  • Blue Shield – see Armstrong Whitworth Sea Slug
  • Blue Silk – airborne Doppler navigation radar unit with lower speed range than Green Satin
  • Blue Sky – see Fairey Fireflash
  • Blue Slug – heavy ship-to-ship missile using Sea Slug launcher, nuclear or conventional
  • Blue Star – satellite launcher – see Black Prince
  • Blue Steel – an air-launched rocket propelled nuclear stand-off missile
  • Blue Stone – Unit 386D ENI – nuclear weapon component
  • Blue Streak – a medium-range ballistic missile
  • Blue Study – automatic blind bombing system for V-bombers
  • Blue Sugar – air-droppable target marking radio beacon developed by TRE
  • Blue Vesta – later version of the Blue Jay air-to-air missile
  • Blue Vixen – pulse-Doppler radar for Sea Harrier FA2
  • Blue Warrior VHF/UHF Jammer – countermeasure to use of radar AA shells
  • Blue Water – nuclear-armed tactical surface-to-surface missile intended for Royal Artillery in West Germany; also see [|Red Rose]
  • Blue Yeoman – early warning radar, also known as AMES Type 85, a component Linesman; name created from the "Blue" of Blue Riband and the Yeoman of Orange Yeoman. Potentially non-official name.

    Brown

  • Brown Bunny – original, unofficial name for Blue Peacock

    Green

  • Green Apple – related to Window for measuring drift at sea
  • Green Archer – mortar-locating radar
  • Green Bacon – experimental anti-aircraft radar for Bofors units
  • Green Bamboo – "hybrid" nuclear weapon design similar to Soviet RDS-6s
  • Green Bottle – 1944 device for homing on U-boat radio signals
  • [|Green Cheese] – nuclear anti-ship missile
  • Green Flash – Green Cheese's replacement
  • Green Flax – surface-to-air guided weapon or surface-to-air missile ; see [|Yellow Temple]
  • Green Garland – infrared proximity fuze for [|Red Top]
  • Green Garlic – early warning radar, also known as the AMES Type 80
  • Green Ginger – surveillance radars – combined installation of AMES Type 88 and AMES Type 89
  • Green Granite – thermonuclear warheads: Green Granite and Green Granite, both tested at Operation Grapple
  • Green Grass – nuclear warhead for Violet Club and Yellow Sun Mark 1 bombs
  • Green Hammock – low-altitude bomber, Doppler navigation
  • Green Janet – portable, nuclear power plant; see Blue Bishop
  • Green Light – SAGW or SAM – see Short Sea Cat
  • Green Lizard – tube-launched SAM with variable geometry wings
  • Green Mace – 5-inch rapid firing anti-aircraft gun
  • Green Minnow – radiometer imager
  • Green Palm – ARI 18074 airborne VHF voice channel jammer with four pre-set channels, replaced in the Vulcan B2 by the I band jammer
  • Green Salad – ARI 18044 wide-band VHF Homing equipment for the Avro Shackleton
  • Green Satin – ARI 5851 airborne Doppler navigation radar unit
  • Green Sparkler – advanced SAM for the "Stage 2" program, became Blue Envoy
  • Green Thistle – infra-red homing system based on the German wartime Kielgerät
  • Green Walnut – blind bombing equipment
  • Green Water – pilotless interceptor/SAGW
  • Green Willow – EKCO AI Mk. 20 Fire Control radar, backup to ARI 5897 AI Mk. 23 Airborne Interception radar for the English Electric P.1 fighter
  • Green Wizard – instrument for calibrating anti-aircraft guns by measuring their muzzle velocity

    Indigo

  • Indigo Bracket – S-band radar jamming system
  • [|Indigo Corkscrew] – continuous wave radar, used with the Bristol Bloodhound and English Electric Thunderbird SAMs
  • Indigo Hammer, formerly Blue Fox – nuclear weapon

    Jade

  • Jade River – continuous wave radar, developed from Indigo Corkscrew

    Orange

  • Orange Blossom – probably a deliberate mis-identification of the Orange Crop pods fitted to 1312 Flight Hercules aircraft, possibly pod-mounted electronic support measures used on the Hercules
  • Orange Cocktail – experimental homing radar weapon from the 1950s
  • Orange Crop – Racal MIR 2 ESM system for Royal Navy Lynx and Royal Navy Sea King helicopters and some Royal Air Force Hercules aircraft
  • Orange Harvest – S and X band warning receiver fitted to Shackletons
  • Orange Herald – large boosted fission nuclear warhead, tested at Operation Grapple in 1957
  • Orange Nell – short-range surface-to-air missile
  • Orange Pippin – Ferranti, anti-aircraft, fire-control radar
  • Orange Poodle – low altitude, OTHR early-warning radar – abandoned
  • Orange Putter – ARI 5800 airborne passive radar warning receiver tuned to Soviet AI radars and fitted to Canberra and Valiant
  • Orange Reaper – Racal "Kestrel" ESM system for Royal Navy Merlin helicopters
  • Orange Tartan – 'Auto-Astro' automated star navigation system – see also Blue Sapphire
  • Orange Toffee – radar for Blue Envoy
  • Orange William – heavy anti-tank missile, canceled, later replaced by Swingfire
  • Orange Yeoman – early warning radar and guidance for Bristol Bloodhound SAGW – a.k.a. AMES Type 82