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The Rainbow Codes were a series of code names used to disguise the nature of various British military research projects. They were mainly used from after the Second World War until 1958, when they were replaced by an alphanumeric code system.


The Ministry of Supply (MoS) initiated the idea because, during World War II, the British realised that although the code-names of some German secret projects could be cryptic, they often provided useful clues as to their nature. For example, basic characteristics of a new German radio navigation device known as Wotan (which used a single radio beam) were inferred by the British before it entered service with the Luftwaffe. This was because the system was named after the one-eyed god of the same name, which offered British scientists a useful hint.[1] The intention of rainbow codes was to clearly and uniquely identify British projects, whilst not providing any hints or clues regarding their characteristics.

Each rainbow code name was constructed from a randomly selected colour, plus a randomly selected noun taken from a list, for example:

  • “Blue” + “Steel” = Blue Steel, a nuclear-armed stand-off missile
  • “Green” + “Mace” = Green Mace, an anti-aircraft (AA) gun.

While most colour and noun combinations were meaningless, some were real names, although quite unrelated to the project they designated. For example, “Black Maria” is also a name for a police van and the “Red Duster” is a name for the Red Ensign, the flag flown by British merchant ships. The names were mostly dropped with the end of the Ministry in 1959. Its functions were transferred to the War Office, the Air Ministry that handled military aviation, and the newly created Ministry of Aviation in charge of civil aviation. After the reorganization, projects were mostly named with randomly selected codes comprising two letters and three digits, e.g. BL755, WE177. However, rainbow codes continue to be used with some modern systems; current examples include the Blue Vixen radar[2] and the Orange Reaper Electronic Support Measures system.




  • Blue Anchor - X-Band CW target illumination radar for Bristol Bloodhound
  • 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 [3][4]
  • 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 - X band anti-aircraft radar
  • Blue Danube - the first British nuclear weapon in service
  • Blue Devil - T4 optical bombsight - drift and ground speed from Green Satin
  • Blue Diamond - AA No7 Radar - anti aircraft radar
  • Blue Diver - ARI (Airborne Radio Installation) 18075 airborne low-band VHF jammer - against metric frequency radar such as Tall King
  • 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
  • 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 (Airborne Radio Installation) 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 - a.k.a. AMES Type 87
  • Blue Moon - see Blue Streak
  • Blue Oak - AWRE Atlas 2 super-computer used for simulation of nuclear explosions
  • Blue Parrot - ARI 5930 I band automatic contour-following radar for Buccaneer - also known as AIRPASS II (AIRPASS=Airborne Interception Radar & Pilot's Attack Sight System)
  • Blue Peacock - ten-kiloton nuclear land mine - also known as Blue Bunny and Brown Bunny; it used the Blue Danube physics package.
  • Blue Rapier - Red Rapier - missiles - see UB.109T
  • Blue Riband - large anti-jamming radar - cancelled 1958 and supplanted by 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 various others.
  • Blue Saga - ARI 18105 airborne radar warning receiver (RWR)
  • Blue Sapphire - system - see also Orange Tartan
  • Blue Sky - see Fairey Fireflash
  • Blue Silk - airborne Doppler navigation radar unit with lower speed range than Green Satin
  • 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 (Electronic Neutron Initiator) - 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.[5]
  • Blue Vesta - a later version of the Blue Jay air to air missile
  • Blue Vixen - Pulse-Doppler radar for Sea Harrier FA2
  • Blue Water - see Red Rose
  • Blue Yeoman - Early Warning radar, also known as AMES Type 85, a component Linesman



  • Green Archer - mortar-locating radar
  • Green Bamboo - nuclear weapon[6]
  • Green Cheese - nuclear anti-ship missile[7]
  • Green Flash - Green Cheese’s replacement
  • Green Flax - Surface-to-Air Guided Weapon (SAGW) or surface to air missile (SAM); 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 - nuclear weapons: Green Granite (small), and Green Granite (large)
  • Green Grass - nuclear weapon
  • Green Janet - portable, nuclear power plant; see Blue Bishop
  • Green Hammock - low-altitude bomber, Doppler navigation
  • Green Light - SAGW or SAM - see Short Sea Cat[8]
  • Green Lizard - tube-launched SAM with variable geometry wings
  • Green Mace - 5-inch rapid firing anti-aircraft gun[9]
  • Green Palm - airborne VHF voice channel jammer with four pre-set channels, replaced in the Vulcan B2 by the I band jammer
  • Green Satin - airborne Doppler navigation radar unit
  • Green Sparkler - advanced SAM for the “Stage 2” program
  • Green Water - pilotless interceptor/SAGW
  • Green Walnut - blind bombing equipment
  • 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




  • Orange Crop - Racal MIR 2 ESM system for Royal Navy Lynx helicopters
  • Orange Harvest - S and X band warning receiver fitted to Shackletons
  • Orange Herald - nuclear weapon
  • Orange Nell - SAGW - surface to air missile
  • Orange Pippin - Ferranti, anti-aircraft, fire-control radar
  • Orange Poodle - low altitude, OTHR (Over-the-Horizon) early-warning radar - abandoned
  • Orange Putter - Tail Warning radar fitted to Canberra and Valiant
  • Orange Reaper - Electronic Support Measures system for Royal Navy Merlin helicopters
  • Orange Tartan - 'Auto-Astro' automated system (day) - see also Blue Sapphire (night).[10]
  • Orange William - Swingfire, anti-tank missile
  • Orange Yeoman - Early Warning radar & guidance for Bristol Bloodhound SAGW - a.k.a. AMES Type 82


  • Pink Hawk - early name for Fairey Fireflash missile. As this was a "reduced" version of the Red Hawk, it is a rare example of Rainbow Codes having some implied meaning, rather than their usual purely deliberately meaningless choice.



  • Red Angel - air-launched anti-ship weapon or "special bomb"[11]
  • Red Beard - nuclear weapon
  • Red Cabbage - Naval radar[12]
  • Red Carpet - X-band radar jammer[12]
  • Red Cat - Air-launched nuclear stand-off missile cancelled 11/54.[12]
  • Red Cheeks - inertially guided bomb[12]
  • Red Dean - large air to air missile
  • Red Drover - airborne radar - see Avro 730
  • Red Duster - Bristol Bloodhound surface to air missile
  • Red Flag - free-fall nuclear bomb - 'Improved Kiloton Bomb' - WE.177
  • Red Flannel - experimental Q band H2S
  • Red Hawk - large missile "downrated" to give Blue Sky
  • Red Heathen - early name for Red Shoes[13]
  • Red Hebe - air to air missile, a replacement for Red Dean
  • Red Light (ECM) - X band jammer for V Bombers, entered service as ARI 18146
  • Red Neck - airborne side-looking radar (SLAR)
  • Red Rapier , Blue Rapier missiles - see UB.109T
  • Red Rose - short-range, battlefield nuclear missile for the British Army - later known as Blue Water; cancelled 1962
  • Red Queen - rapid fire 42 mm revolver cannon anti-aircraft gun [14][15]
  • Red Sea (AA) - the AA predictor designed for use with the Green Mace automatic AA gun[16]
  • Red Setter - experimental side-looking radar for V bombers
  • Red Shoes - see English Electric Thunderbird
  • Red Shrimp - ARI 18076 airborne high-band jammer fitted to Victor & Vulcan
  • Red Snow - nuclear weapon physics package - Unit 10,000 fitted to Yellow Sun Mk2 and Blue Steel
  • Red Steer - EKCO ARI 5919/ARI 5952 airborne tail-warning radar - development of AI 20 Green Willow
  • Red Top - air to air missile also known as Firestreak Mk 4
  • Red Ticket - associated with AI 17 radar
  • Red Tulip - phase coherent radar Moving Target Indicator (MTI)



Non-Rainbow codes

Several British military related terms have a similar format to Rainbow Codes, but are not since they do not refer to classified research projects. These include:

  • Blue Circle - sardonic name for concrete ballast for Buccaneer while awaiting Blue Parrot radar - later also used for Tornado F.2 ballast - from the Blue Circle cement company
  • Green Goddess - Colloquial name for Civil Defence fire pump
  • Green Porridge - RAF aircrew nickname for green-tinted H2S bombing radar display PPI image in Valiant, Victor & Vulcan
  • Red Arrows - RAF display team
  • Red Devils - Parachute Regiment display team
  • Red Slab - joke name for a large ballast weight replacing the nose radar in Avro Vulcan XH558 in its return to flight as a civil display aircraft.
  • Violet Fire - Ultraviolet light fire detection system for Concorde engine bays.[18]

See also


  1. Jones, R (1978). Most Secret War. London: Hamish Hamilton Ltd.. p. 120. ISBN 0-241-89746-7. 
  2. "Blue Vixen radar (United Kingdom), AIRBORNE RADAR SYSTEMS". Jane's Avionics. Retrieved 2009-08-08. 
  3. Boar
  4. 7
  5. Chris Gibson Vulcan’s Hammer p.18
  6. PRO. AVIA 65/1193 E10A. Tech Note GW375 p.2
  7. "Fairey Green Cheese Air to Surface missile". Skomer. 
  8. Cullen, Tony & Foss, Christopher F. (1991) Jane’s Land-Based Air Defence 1990–91, Jane’s Information Group, London: ISBN 0-7106-0915-9
  9. Green Mace Anti-Aircraft Gun
  10. Chris Gibson Vulcan's Hammer p17
  11. British Secret Projects: Jet Bombers Since 1949 Tony Buttler Midland Publishing 2003
  12. 12.0 12.1 12.2 12.3 "United Kingdom Aerospace and Weapons Projects". Skomer. Retrieved 2012-09-28. 
  14. The Red Queen and the Vigilante accessed 22nd April 2008
  15. Red Queen
  16. Jobson P. (2008) Royal Artillery Glossary of Terms and Abbreviations, The History Press, Stroud: 316 pp.
  17. "Airborne DF has existed for over 50 years.". PPRuNe - Professional Pilots Rumour Network. 22 September 2010. 
  18. Davis, R.A. (1993). "Concorde Power Plant Fire Protection System". pp. 26–30. 

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