Anomalously numbered roads in Great Britain explained

In the Great Britain road numbering scheme, the country is divided into numbered zones, the boundaries of which are usually defined by single-digit roads. The first digit of a road's number should be the number of the zone it occupies. If the road occupies multiple zones, then the furthest-anticlockwise zone is the correct one. The following tables list all British roads which are anomalously numbered. Roads in bold lie completely outside their "correct" zone; all other roads run for some length in their "correct" zones but trespass into zones anticlockwise of this zone. A further table lists duplicated road numbers.

Motorways

The motorway zone boundaries[1] are different from the A-road boundaries.

Road numberLocationTrespassed zoneReason
M48Gloucestershire, MonmouthshireZone 5This road used to be the M4, and as it lies to the north of the current M4 and to the west of the M5, it is in the Motorway Zone 5.[2] [3]
M49Bristol, GloucestershireZone 3This motorway lies entirely within zone 3.[4] The motorway was constructed at the same time as the Second Severn Crossing, and it is likely that the sequential M48 and M49 were used for the old M4 and the new motorway respectively.
M62Merseyside, Greater ManchesterZone 5The section from Liverpool to Manchester was planned as M52, but was added to the M62 to make a cross-country route.
M65LancashireZone 5The short link to the A582 is out of zone

While the M25 may appear to contradict these rules as it runs through all the London-bound zones, it in fact does not: it does not quite form a complete circle. It starts in Zone 2, south of the Thames, and proceeds clockwise through zones 3, 4 and 1. The A282, which completes the circle mostly formed by the M25, is anomalously numbered; as it proceeds into the A-road 1-zone (and should therefore begin with a 1).

The M271 is numbered as a spur of the M27, as opposed to the traditional numbering rules; however the M3 to Southampton came after the M271 was built and is not the zone boundary, which appears to be a straight line from M3 J8 to Exeter in some documentation.

A roads

Road numberLocationTrespassed zone(s)Reason
A14NorthamptonshireZone 5 & 6The A14 was chosen as a unique, important number for this crucial cross-country route.
A31SurreyZone 2Formerly north-east of the A3 before the Guildford Bypass.
A42LeicestershireZone 5The A42 is numbered as an extension of the M42.
A51WarwickshireZone 4Extended over an orphaned section of the A423 when part of that road NW of Coventry was downgraded to B class.
A55AngleseyZone 4The A55 supersedes the A5 through Anglesey.
A66CumbriaZone 5The A66 was extended westwards beyond the A6 to make it a coast-to-coast route.
A88FalkirkZone 9Planned to extend westwards to form the A80 to Kincardine Bridge road - this instead became the M876.
A89GlasgowZone 7The A89 through Glasgow used to be partly the A8.
A91StirlingZone 8Rerouted to bypass Stirling. Meets the A9 at Greencornhills Roundabout yet continues into Zone 8 as far as the Bannockburn Interchange.
A167DurhamZone 6The A167 through Durham used to be part of the A1.
A168North YorkshireZone 6The A168 originally only went from Northallerton to Dishforth, and was extended by the former A1 when it was upgraded in 1994, changing the most westerly point to a different zone.
A177DurhamZone 6In County Durham the original A1 route (now A167), not the A1(M) motorway, forms the zone boundary.
A181DurhamZone 6In County Durham the original A1 route (now A167), not the A1(M) motorway, forms the zone boundary.
A199East LothianZone 6The A199 used to be part of the A1. (With respect to the Scottish numbering hub of Edinburgh, the A199 is in fact correctly numbered as Zone 1 is anticlockwise from Zone 6 when viewed this way.)
A282ThurrockZone 1New road which is important and assigned an A2xx number as most A1xx numbers were already used (as zone 1 is far larger than zone 2). Could be A108 or A122, both unused numbers at present.
A307SurreyZone 2The A307 used to be part of the A3.
A320SurreyZone 2Formerly north-east of the A3 before the Guildford Bypass.
A322SurreyZone 2Formerly north-east of the A3 before the Guildford Bypass.
A397PortsmouthZone 2The A397 used to be part of the A3.
A404Windsor and MaidenheadZone 3The A404 originally began on the A4 1.7 miles west of where it now passes under where the A404(M) passes under the A4 and loses its motorway status. The change in route took place in September 1992 when the A404 was rerouted and took over the what was previously the A423(M) which itself had originally been part of the M4.
A412SloughZone 3The A412 begins in Zone 3, at the A332.
A427NorthamptonshireZone 6The A427 previously ran from Coventry to Oundle, and was truncated west of Market Harborough, when the new A14 opened. This section was renumbered as the B4027, A4303 and A4304. An even older alignment (pre-c.1960s) heading south from North Kilworth as far as the A45 is now an unclassified road (formerly B5414) and A4071.
A447LeicestershireZone 5Route south of the A47 decommissioned, leaving the remainder out-of-zone.
A505BedfordshireZone 4The A505 was extended to become a cross-country route.
A601DerbyZone 5Chosen as a unique number for the Derby inner ring road.
A620NottinghamshireZone 1The A620 was truncated and left east of the A1.
A624Chapel-en-le-Frith, DerbyshireZone 5The A624 was part of the A6 for a short stretch in Chapel-en-le-Frith before the Chapel By-pass was built.
A683LancashireZone 5The A683 was extended westwards to Heysham docks.
A689CumbriaZone 5The A689 was extended south-westwards around Carlisle from M6 J44 to the A595 in the 5 zone. (It passes through the 7 zone as well between the A7 and River Eden, but the actual boundary between the 5 and 7 zones is undefined, and a road crossing the A7 would be correctly numbered starting 6, as zone 6 is anticlockwise of zone 7 as viewed from the numbering hub of Edinburgh.)
A720EdinburghZone 6The A720 bypasses the numbering hub of Edinburgh, making numbering difficult; A720 was chosen for apparent importance. Most important 6-zone numbers were all used. Also notably distant from all other A72x roads.
A882HighlandZone 9The A9 was rerouted to terminate at Scrabster rather than John O'Groats, leaving the A882 in zone 9.
A899West LothianZone 7The A899 was extended south through Livingston new town, Scotland.
A904FalkirkZone 8The A9 was rerouted to bypass Falkirk town centre.
A949HighlandZone 8The A949 used to be part of the A9.
A1000HertfordshireZone 6The A1000 used to be part of the A1.
A1057HertfordshireZone 6The A1057 used to be part of the A1.
A1068NorthumberlandZone 6The A1 was rerouted around Alnwick, leaving the end of A1068 out-of-zone.
A1081HertfordshireZone 6The A1081 used to be part of the A6.
A1246North YorkshireZone 6The A1246 used to be part of the A1.
A3023HampshireZone 2The A3023 was originally the B2149.
A3100SurreyZone 2The A3100 used to be part of the A3.
A3400WarwickshireZone 4The road was numbered to reflect its history as the old A34.
A4174BristolZone 3The A4174 is part of the Bristol outer ring road. It was entirely in zone 4 but has been extended to the A4 and then south of it.
A4208LondonZone 3Truncation of the A4 left the A4208 out-of-zone.
A4300NorthamptonshireZone 5The A4300 used to be part of the A43.
A4303LeicestershireZone 5The A4303 used to be part of the A427.
A4304LeicestershireZone 5The A4304 used to be part of the A427.
A4500NorthamptonshireZone 5The A4500 used to be part of the A45.
A4501NorthamptonshireZone 5The A4501 used to be part of the A45.
A5127Staffordshire, West MidlandsZone 4The A5127 was extended south when the A38 bypassed Sutton Coldfield. The entire A5127 was part of the original route of the A38.
A5140BedfordshireZone 4Much of the route became A421 when it was extended, leaving only the section in Bedford, which is out-of-zone as it is east of the A6.
A5153AngleseyZone 4The A5153 lies south of the A5.
A5154AngleseyZone 4The A5154 used to be part of the A5.
A5223TelfordZone 4Route begins south of the A5.
A6004LeicestershireZone 5The A6004 used to be part of the A6.
A6010ManchesterZone 5The A6010 is part of the Manchester ring road.
A6143ManchesterZone 5The A6143 was originally part of the A57.
A6144TraffordZone 5The A6144 used to be the B5166, B5311 and B5158.
A6182DoncasterZone 1The A1 was rerouted leaving the A6182 out-of-zone.

B roads

Road numberLocationTrespassed zoneReason
B197HertfordshireZone 6The B197 used to be part of the A1
B316LondonZone 4A4 rerouted
B325LondonZone 4A4 rerouted
B384West MidlandsZone 4Used to be part of the A38, and numbered to match. (Initially numbered B38 by Birmingham City Council.)
B455LondonZone 3A4 rerouted
B470Windsor and MaidenheadZone 3
B576NorthamptonshireZone 6A6 rerouted
B589LoughboroughZone 6Route now runs on the wrong side of the A6.
B645NorthamptonshireZone 5A6 rerouted
B704MidlothianZone 6Extends through Gorebridge whilst A7 forms western bypass.
B708West LothianZone 8Was previously numbered as B8708[5] in keeping with the scheme.
B855HighlandZone 9The A9 was rerouted west of this road, to end at Scrabster.
B876HighlandZone 9The A9 was rerouted west of this road, to end at Scrabster.
B1043CambridgeshireZone 6The B1043 used to be part of the A1.
B1164NottinghamshireZone 6The B1164 used to be part of the A1.
B1198DurhamZone 6In County Durham the original A1 route (now A167), not the A1(M) motorway, forms the zone boundary.
B1217LeedsZone 6extended along old A642 when M1 extended
B1224North YorkshireZone 6In County Durham the original A1 route (now A167), not the A1(M) motorway, forms the zone boundary.
B1284DurhamZone 6In County Durham the original A1 route (now A167), not the A1(M) motorway, forms the zone boundary.
B1350EdinburghZone 9Although the B1350 is a continuation of London Road the remaining mile of the A1 is to the south at this point.
B2215SurreyZone 2The B2215 used to be part of the A3.
B3000SurreyZone 2A3 rerouted
B3004HampshireZone 2A3 rerouted
B3006HampshireZone 2A3 rerouted
B3345ReadingZone 4A4 rerouted
B3800West MidlandsZone 4The B3800 used to be part of the A4040.
B4640West BerkshireZone 3Formerly a portion of the pre-bypass A34; unknown why B4640 was chosen as it has no relation to the A34.
B4666Hinckley, LeicestershireZone 5The B4666 used to be part of the A47.
B4667Hinckley, LeicestershireZone 5The B4667 used to be part of the A447.
B4668Hinckley, LeicestershireZone 5The B4668 used to be part of the A47.
B4669LeicestershireZone 5Originally numbered B579 and later became A5070. A5070 was renumbered B4069 following completion of the M69, and gained its present number around 1990 as part of a renumbering plan in Hinckley.
B5010East MidlandsZone 6A5 rerouted
B5011BrownhillsZone 4Section north of the A5 declassified, leaving the southern section out-of-zone.
B5061ShropshireZone 4A5 rerouted
B5070WrexhamZone 4The B5070 used to be part of the A5.
B5072TelfordZone 4A correct zone B5072 existed in Nantwich until the 1930s. Became part of A530.
B5444SwanseaZone 4Originally part of the B4292 until it was upgraded in the 1960s as A4217. When the central section was rerouted, the bypassed section was returned to Class II status with the current number, despite it being a duplicate and out-of-zone.
B5477ShropshireZone 4This was, until renumbered in 2004, the northern section of the B4370 (Little Stretton - Church Stretton - All Stretton); additionally the number was (and remains) in separate use in Wallasey.
B6000DerbyZone 5A6 rerouted
B6184StockportZone 5The B6184 used to be part of the B5465.
B6241Preston, LancashireZone 5The B6241 was extended west of the A6.
B6280DarlingtonZone 1In County Durham the original A1 route (now A167), not the A1(M) motorway, forms the zone boundary.
B6291DurhamZone 1The original section within Zone 6 was renumbered to become an extension of the A688.
B6420NottinghamshireZone 1The A1 was re-routed, leaving its start-point out of zone.
B6469ManchesterZone 5Originally numbered A57 west of the A6 and A635 to the east; probably downgraded due to construction of the A57(M).
B6541MiddlesbroughZone 1The B6541 used to be part of the A66.
B7201Dumfries and GallowayZone 6The B7201 was part of the A7 before bypass of Canonbie; was B720 beforehand.
B8046West LothianZone 7The B8046 was extended beyond both the old A8 and the M8 as far as Mid Calder, absorbing the B767.[6]
B9080West LothianZone 8The B9080 used to be part of the A9.
B9150HighlandZone 8The B9150 used to be part of the A9.
B9163HighlandZone 8A9 rerouted
B9164HighlandZone 8A9 rerouted
B9169HighlandZone 8A9 rerouted
B9176HighlandZone 8The B9176 used to be part of the A9
B9177HighlandZone 8The B9177 used to be part of the A9

Irregularities not based on the zoning system

Road numberLocationReason
A135Stockton-on-TeesThe other A13x roads are in southern England.
A139Stockton-on-TeesThe other A13x roads are in southern England.
A176Basildon, EssexThe other A17x roads are in North Yorkshire or County Durham.
A180GrimsbyThe other A18x roads are in the North-east. The A180 is numbered as an extension of the M180.
A249Maidstone - Sheerness, KentThe other A24x roads are in Surrey.
A303Hampshire - SomersetThe other A30x roads are in Surrey and Southwest London.
A403Avonmouth, South GloucestershireThe other A40x roads are in or around Greater London
A437Hillingdon, Greater LondonThe other A43x roads are in Gloucestershire, Oxfordshire or Warwickshire.
A491Bromsgrove - StourbridgeThe other A49x roads are in North Wales.
A500Stoke-on-Trent "D"-roadThe other A50x roads are in London, southern England and Northamptonshire
A506LiverpoolThe other A50x roads are in London, southern England and Northamptonshire
A598Barnet, Greater LondonThe other A59x roads are in Cumbria (but see A594 below)
A720Edinburgh City Bypass, EdinburghThe other A72x roads are mostly to the south and southeast of Glasgow.
A1018Tyne and WearThe other A101x roads are in East London and Essex
A1300South ShieldsThe other A130x roads are in Essex and Cambridgeshire.
A1305Stockton-on-TeesThe other A130x roads are in Essex and Cambridgeshire.
A2022London & SurreyThe other A202x roads are in Sussex.
A2219CrawleyThe other A220x and A221x roads are in London.
A2220CrawleyThe other A220x and A221x roads are in London, (there are no other A222x roads)
A3031South LondonThe other A303x roads are in Southwest England.
A3036South LondonThe other A303x roads are in Southwest England. The route used to be the A303, before it got moved to its current route.
A3113London Heathrow AirportThe other A311x roads are on the Isles of Scilly.
A4010BuckinghamshireThe other A401x roads are in Cheltenham and Bristol.
A4012BedfordshireThe other A401x roads are in Cheltenham and Bristol.
A4020West LondonThe other A402x roads are in the West Midlands. The road is numbered after the A402 road, which the A4020 terminates on at its eastern end at Shepherd's Bush.
A4032BristolThe other A403x roads are in the West Midlands.
A4041West MidlandsThe other A404x roads are in the country of Wales.
A4053Coventry Ring Road, CoventryThe other A405x roads are in the country of Wales.
B77MayboleAll other B roads in Great Britain are three or four digits.

Two clearly separate roads with the same number

Road numberLocationsNotes
A479Brecon BeaconsWembley
A594 (Cumbria/Leicester)CumbriaLeicesterThe Cumbria version predates the Leicester version.
A728South GlasgowNorth Glasgow
A1042RedcarNorwichThe Redcar version predates the Norwich version.
A1056Newcastle upon TyneNorwichThe Newcastle version predates the Norwich version.
A1114ChelmsfordGateshead
A1199IslingtonWoodfordBoth are in Greater London.
A1243Great Yarmouth
A4102AmblecoteThe Amblecote version predates the Merthyr Tydfil version.
A5028SeacombeNorthamptonshire
A5152WrexhamAnglesey
A5271Stoke-on-Trent
A6013Derbyshire
B454Kingsbury, LondonWest London
B667LeicesterThurmaston
B1140NorwichWroxham
B1172SpaldingNorfolk
B2122SurreyBrighton
B3153SomersetWeymouth
B3165SomersetSurrey
B3206DevonSurrey
B3330WinchesterIsle of Wight
B3331WinchesterIsle of Wight
B3440Weston-super-MareDevon
B4065DroitwichWarwickshire
B4082WorcestershireCoventry
B4100BirminghamOxfordshire, Warwickshire
B4104MeridenKenilworth
B4105CoventrySolihull
B4118BirminghamCoventry
B4122BirminghamWiltshire
B4587DudleyWiltshire
B4624LlandysulEvesham
B5120DunstablePrestatyn
B5142WirralWeaverham
B5144WirralWeaverham
B5192KirkbyKirkham WirralOnly number that exists in three locations.
B5207NethertonLancashire
B5210Central WarringtonWarrington
B5444MoldSwansea The Swansea version is out-of-zone.
B5477WallaseyChurch Stretton The Church Stretton version is out-of-zone.
B6135DrighlingtonYorkshire
B6265North YorkshireWest Yorkshire
B6322HaltwhistleConsett
B6374RoxburghshireDerbyshire
B6452GalashielsRochdale
B9178Dulnain BridgePeterhead

References

External links

Notes and References

  1. Web site: How the Motorways were Numbered . Pathetic Motorways . 12 May 2010 .
  2. Web site: Motorway Database - M48 . CBRD . 2007-10-26.
  3. Web site: Pathetic Motorways.
  4. Web site: How the Motorways were Numbered . Pathetic Motorways . 1 September 2006 . https://web.archive.org/web/20060902113742/http://pathetic.org.uk/features/numbering/. 2 September 2006 . live.
  5. Web site: Side by side georeferenced maps viewer - Map images - National Library of Scotland.
  6. Web site: Side by side georeferenced maps viewer - Map images - National Library of Scotland.

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