1920-1929
| Spec. | OR | Type | Designs (accepted and tendered) |
| 1/20 | None | First spec. issued: spares carrier | Bristol Type 37 Tramp |
| 2/20 | 'Interim' single-engine heavy bomber | Avro Aldershot, De Havilland DH.27 Derby | |
| 3/20 | Single-seat deck-landing torpedo-carrier - Spec. superseded by 32/22 (q.v.) | Blackburn Dart (modified), Handley Page H.P.19 Hanley | |
| 4/20 | Long-distance photographic and reconnaissance aeroplane | Boulton & Paul Bolton | |
| 5/20 | Troop Carrier Biplane | Bristol Type 56, Vickers Victoria | |
| 6/20 | Vimy Ambulance | Vickers Vimy Ambulance | |
| 7/20 | Fleet reconnaissance and fleet spotting amphibian | Supermarine Seagull | |
| 8/20 | 3-seat reconnaissance aircraft for Army/Navy | Armstrong Whitworth Tadpole, Westland Walrus | |
| 9/20 | Medium range postal monoplane | Parnall Possum, Boulton & Paul Bodmin | |
| 10/20 | Cantilever monoplane | de Havilland Doncaster | |
| 11/20 | Parnall Possum, Boulton & Paul Bodmin | ||
| 1/21 | Long-range bomber - Vimy replacement | Vickers Virginia III | |
| 2/21 | Experimental single-seat convertible biplane/monoplane fighter/interceptor/two-seat reconnaissance-fighter aircraft - written for Bullfinch | Bristol Bullfinch | |
| 3/21 | Naval Fleet spotter/reconnaissance aircraft | Avro Bison, Blackburn Blackburn | |
| 5/21 | Light day bomber - DH.9A replacement | Fairey Fawn | |
| 7/21 | Parnall Plover | ||
| 13/21 | Handley Page H.P.20 | ||
| 19/21 | Two-seat reconnaissance aircraft - Bristol Fighter replacement | Short Springbok | |
| 1/22 | Vickers Vanguard | ||
| 3/22 | Two-seat fighter/reconnaissance powered by a supercharged engine - Bristol Fighter replacement | Bristol Bloodhound | |
| 6/22 | Naval carrier fighter with interchangeable wheel & float undercarriages using Jaguar or Jupiter engine - Nightjar replacement | Fairey Flycatcher, Parnall Plover | |
| 7/22 | Army reconnaissance aircraft | Hawker Duiker | |
| 14/22 | Armstrong Whitworth Siskin III | ||
| 15/22 | Fighter/interceptor | Armstrong Whitworth Siskin III | |
| 16/22 | Long range Torpedo Bomber to carry 21 inch torpedo | Blackburn Cubaroo, Avro 557 Ava | |
| 21/22 | Twin-engined amphibian flying boat for civil operations - see also R.18/24 | Supermarine Swan | |
| 22/22 | Two-seat fighter/reconnaissance powered by a supercharged engine - Bloodhound three aircraft order - revised from 3/22 (q.v.) | Bristol Bloodhound | |
| 25/22 | Single-seat night interceptor fighter | Hawker Woodcock | |
| 30/22 | Boulton & Paul Bugle | ||
| B.30/22 | Heavy bomber - written for Bugle II production order but Sidestrand also apparently designed to this spec. | Boulton Paul Bugle II, Boulton Paul Sidestrand | |
| 31/22 | 4-seat heavy night-bomber | Handley Page Hyderabad | |
| 32/22 | Single-seat deck-landing torpedo-carrier - Spec. supersedes 3/20 (q.v.) | Blackburn Dart II, Bristol Brandon | |
| 37/22 | Three-seat deck landing reconnaissance aircraft - Blackburn/Bison replacement | Blackburn Airedale, Hawker Hedgehog | |
| 38/22 | General Purpose seaplane/landplane | Fairey IIID | |
| 40/22 | Transport aeroplane - civil airliner - larger version of DH.34 | de Havilland Highclere | |
| 41/22 | 'Middle East type transport aeroplane' - civil airliner | Armstrong Whitworth Argosy, de Havilland Hercules | |
| 43/22 | Vickers Vernon II | ||
| 44/22 | Single-engined long-range reconnaissance seaplane - intended for round-the-World flight | Fairey Fremantle | |
| 16/23 | None | Spotting ship-plane | Avro Bison |
| 19/23 | Fighter/interceptor - improved Siskin III | Armstrong Whitworth Siskin IIIA | |
| 21/23 | Fleet two-seat torpedo bomber | Avro Buffalo, Blackburn Ripon, Handley Page H.P.31 Harrow | |
| 23/23 | Coastal patrol and anti-submarine flying-boat | English Electric Kingston | |
| 25/23 | Fleet two-seat torpedo bomber/bomber | Handley Page H.P.25 Hendon | |
| 26/23 | Two-seat long-range day-bomber | Bristol Berkeley, Handley Page H.P.28 Handcross, Hawker Horsley, Westland Yeovil | |
| 28/23 | Long-range bomber - Virginia production order | Vickers Virginia | |
| 37/23 | Single-engined fighter/interceptor - improved Grebe | Gloster Gamecock | |
| 1/24 | Three-seat fleet reconnaissance seaplane and amphibian | Parnall Pike, Short S.6 Sturgeon, Bristol Type 87 | |
| 2/24 | Light Aeroplane | Cancelled | |
| 3/24 | Single-seat high-performance landplane | Hawker Woodcock II (production) | |
| 4/24 | "Twin-Engined Home Defence Fighter" armed with two 37 mm cannons | Westland Westbury Bristol Bagshot | |
| 5/24 | Advanced landplane, convertible to a seaplane, trainer for RAF and deck-landing trainer for FAA | Cancelled replaced by 5A/24 | |
| 5A/24 | Floatplane trainer | Vickers Vendace, Blackburn Sprat, Parnall Perch | |
| 6/24 | Single-seat fighter | Fairey Flycatcher I (production) | |
| 7/24 | 'High Powered Single-Seater Fighter Landplane' | Avro Avenger, Fairey Firefly, Fairey Fox, Gloster Gorcock, Hawker Hornbill | |
| 8/24 | Army co-operation aircraft | de Havilland Dingo | |
| 9/24 | Twin engine medium day-bomber - Sidestrand II production order - see also 25/27 | Boulton Paul Sidestrand II | |
| 10/24 | Fleet spotting ship-plane | Blackburn Blackburn | |
| 11/24 | Fleet spotting ship-plane | Avro Bison II | |
| 12/24 | Long-range bomber - Virginia production order | Vickers Virginia | |
| 13/24 | Patrol flying boat | Blackburn Iris III, Short Singapore | |
| 14/24 | Three-engined boat seaplane | Blackburn Iris, Saunders Valkyrie | |
| 15/24 | 4-seat heavy night-bomber - initial production batch of Hyderabads | Handley Page Hyderabad I | |
| 16/24 | Submarine-borne reconnaissance seaplane | Parnall Peto | |
| 17/24 | Single-seat high-speed fighter landplane | Gloster Guan | |
| 18/24 | Twin-engined amphibian flying boat - military version of boat ordered to 21/22 | Supermarine Southampton | |
| 19/24 | Three-seat Spotter/Reconnaissance (FAA) /two-seat GP (RAF) aircraft with interchangeable land & float U/C & folding wings | Fairey IIIF | |
| 20/24 | All-metal monoplane flying boat | Beardmore Inverness | |
| 21/24 | Single-seat boat seaplane for storage in restricted space | Parnall Prawn | |
| 22/24 | Three-engine boat seaplane | Saunders Valkyrie | |
| 23/24 | Twin engine civil airliner | Handley Page H.P.32 Hamlet | |
| 24/24 | Conversion of Bison I to Bison Ia | Avro Bison | |
| 25/24 | Single-seater, high-speed fighter landplane | Hawker Heron | |
| 26/24 | Three-engined landplane for dutied in the Middle East | Cancelled | |
| 27/24 | Twin engine single-seat interceptor/night fighter | Boulton Paul Bittern | |
| 28/24 | Day and night fighter - Siskin replacement | Armstrong Whitworth Starling | |
| 29/24 | Twin-engined boat amphibian with Lynx engines (service aircraft) | Supermarine Seamew | |
| 30/24 | Two-seat reconnaissance/army co-operation aircraft | de Havilland Hyena, Short Chamois, Vickers Vespa | |
| 31/24 | Twin-engined boat amphibian with Lynx engines (civil aircraft) | Saunders Medina | |
| 32/24 | Training landplane with Lynx engines - replaced by 3/27 | Avro 504N | |
| 33/24 | Three-engined boat seaplane for civil use | Not issued | |
| 34/24 | Freight carrying landplane | Vickers Vellore, Gloucester Goodwood | |
| 35/24 | Three-engine landplane for Middle East transport | Armstrong Whitworth Argosy | |
| 11/25 | Supermarine Southampton | ||
| 17/25 | Naval single-seater fighter of all-metal stressed-skin construction with interchangeable wheel and float U/C powered by Lynx engine | Avro 584 Avocet, Vickers Vireo | |
| 20/25 | Army co-operation aeroplane - Bristol Fighter/DH.9A replacement | Armstrong Whitworth Atlas, Bristol Boarhound | |
| 23/25 | Two-seat day-bomber, reconnaissance & coastal torpedo-bomber | Blackburn Beagle, Gloster Goring, Handley Page H.P.34 Hare, Hawker Harrier, Westland Witch | |
| 24/25 | High altitude bomber - Horsely replacement | Blackburn Beagle, Handley Page H.P.34 Hare, Vickers Vildebeest | |
| 7/26 | Twin-float high-speed monoplane seaplane for 1927 Schneider Trophy competition | Short Crusader | |
| F.9/26 | None | Day and night 'zone' fighter - no design accepted and Spec. superseded by F.20/27 (q.v.) | Armstrong Whitworth Starling II, Blackburn Blackcock/Turcock, Boulton Paul Partridge, Bristol Bulldog Mk.I, Bristol Bullpup, Gloster Goldfinch, Gloster SS.18, Hawker Hawfinch, Vickers Type 141 |
| 10/26 | Long-range bomber - Virginia production order | Vickers Virginia | |
| 12/26 | Fast two-seat day bomber of all-metal construction using Rolls-Royce F.XIB engine | Avro Antelope, Hawker Hart, Fairey Fox IIM | |
| 14/26 | Passenger flying boat | Short Calcutta | |
| 21/26 | Naval Fleet fighter - see also N.21/26 | Parnall Pipit, Vickers Type 141, Vickers Type 177 | |
| N.21/26 | Naval Fleet fighter - see also 21/26 | Armstrong Whitworth Starling II, Armstrong Whitworth AW XVI, Blackburn Blackcock/Turcock, Fairey Firefly III, Gloster Gnatsnapper, Hawker Hoopoe, Vickers Type 177 | |
| O.22/26 | Naval high-speed, two-seat, Fleet fighter/reconnaissance | Blackburn Nautilus, Fairey Fleetwing, Handley Page H.P.37F, Hawker Osprey, Short Gurnard | |
| R.4/27 | Maritime patrol flying boat | Saunders Severn | |
| R.5/27 | Reconnaissance flying boat | Blackburn Sydney | |
| 8/27 | Long-range bomber - Virginia production order | Vickers Virginia | |
| F.10/27 | Single-seat fighter armed with six machine guns | Saunders A.10 | |
| B.19/27 | Twin engine night-bomber - Virginia/Hinaidi replacement - Hendon winner but introduction delayed so runner-up (Heyford) accepted | Avro Ava, Fairey Hendon, Handley Page Heyford, Vickers Type 150, Vickers Type 163, Vickers Type 195, Vickers Type 225, Bristol Type 108 | |
| C.20/27 | Transport version of Hyderabad/Hinaidi - Chitral/Clive | Handley Page Clive | |
| F.20/27 | 'Interception single-seat fighter' | Armstrong Whitworth Starling II, Bristol Bulldog Mk.II, de Havilland DH.77, Fairey Firefly II, Hawker Fury, Saunders A.10, Vickers Jockey, Westland Interceptor | |
| B.22/27 | Three engine night-bomber - abandoned due to delays and replaced by B.19/27 (q.v.) | Boulton Paul P.32, de Havilland DH.72 Canberra | |
| 25/27 | Twin engine medium day-bomber - Sidestrand II production order - see also 9/24 | Boulton Paul Sidestrand II | |
| 26/27 | General purpose aircraft - D.H.9A replacement | Bristol Beaver, de Havilland Hound, Fairey Ferret, Gloster Goral, Vickers Valiant, Vickers Venture, Vickers Vixen, Westland Wapiti | |
| F.29/27 | Fighter utilizing a 37 mm cannon from Coventry Ordnance Works | Vickers Type 161, Westland C.O.W. Gun Fighter, Bristol Type 112 | |
| 33/27 | 'Postal Aircraft' - experimental very-long range aeroplane for world distance-record attempt | Fairey Long-range Monoplane | |
| M.5/28 | Torpedo bomber - Spec superseded by M.1/30 (q.v.) | Handley Page H.P.41 | |
| R.6/28 | Patrol/reconnaissance flying boat | Short Sarafand | |
| 8/28 | Racing seaplane for 1929 Schneider Trophy using Rolls-Royce R engine, for use by RAF High Speed Flight | Supermarine S.6 | |
| 13/28 | Long-range bomber - Virginia production order | Vickers Virginia | |
| C.16/28 | Bomber-transport capable of carrying 30 fully armed troops, or their equivalent in cargo or bombs, for a distance of 1,200 mls (1,931 km) nonstop | Gloster TC.33, Handley Page H.P.43, Vickers Type 163, Bristol Type 115, Bristol Type 116 | |
| F.17/28 | Bulldog II production order | Bristol Bulldog Mk.II | |
| 21/28 | High-speed mailplane for Imperial Airways | Boulton Paul P.64 Mailplane, Boulton Paul P.71A | |
| 1/29 | General purpose aircraft (for production) | Westland Wapiti | |
| 2/29 | Two-seat carrier-borne torpedo-bomber (for production) | Blackburn Ripon IIA | |
| 3/29 | Troop transport aircraft | Handley Page Clive II | |
| 4/29 | Ab initio trainer - Moth with Gypsy I order | de Havilland Moth | |
| 5/29 | Elementary trainer (for production) | Hawker Tomtit | |
| 6/29 | General purpose landplane | Blackburn CA.15, Boulton & Paul P.42, Westland Limousine V | |
| 7/29 | Troop carrying aeroplane (for production) | Vickers Victoria V | |
| 8/29 | Single-seat fighter (for production) | Armstron Whitworth Siskin IIIA | |
| 9/29 | Day bomber (for production) | Hawker Hart | |
| 10/29 | Medium day-bomber (for production) | Boulton Paul Sidestrand III | |
| 11/29 | Day and night fighter (for production) | Bristol Bulldog IIA | |
| 12/29 | Spotter reconnaissance aeroplane for the Fleet Air Arm (for production) | Fairey IIIF | |
| 13/29 | Heavy night-bomber (for production) | Handley Page Hinaidi II | |
| 14/29 | Army co-operation aircraft | Cancelled | |
| 15/29 | General purpose aircraft | Cancelled | |
| 16/29 | Experimental tailless aircraft | Westland-Hill Pterodactyl IV | |
| 17/29 | All-metal torpedo-bomber (for development and production) | Hawker Horsley | |
| 18/29 | General reconnaissance flying boat - military version of Calcutta | Short Rangoon |
Read more about this topic: List Of Air Ministry Specifications, List of Specifications (incomplete)