# Anomalously numbered roads in Great Britain

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 are different from the A-road boundaries.
| Road number | Location | Trespassed zone | Reason |
| M48 | Gloucestershire, Monmouthshire | Zone 5 | This 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. |
| M49 | Bristol, Gloucestershire | Zone 3 | This motorway lies entirely within zone 3. 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. |
| M62 | Merseyside, Greater Manchester | Zone 5 | The section from Liverpool to Manchester was planned as M52, but was added to the M62 to make a cross-country route. |
| M65 | Lancashire | Zone 5 | The 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 number | Location | Trespassed zone(s) | Reason |
| A14 | Northamptonshire | Zone 5 & 6 | The A14 was chosen as a unique, important number for this crucial cross-country route. |
| A31 | Surrey | Zone 2 | Formerly north-east of the A3 before the Guildford Bypass. |
| A42 | Leicestershire | Zone 5 | The A42 is numbered as an extension of the M42. |
| A51 | Warwickshire | Zone 4 | Extended over an orphaned section of the A423 when part of that road NW of Coventry was downgraded to B class. |
| A55 | Anglesey | Zone 4 | The A55 supersedes the A5 through Anglesey. |
| A66 | Cumbria | Zone 5 | The A66 was extended westwards beyond the A6 to make it a coast-to-coast route. |
| A88 | Falkirk | Zone 9 | Planned to extend westwards to form the A80 to Kincardine Bridge road - this instead became the M876. |
| A89 | Glasgow | Zone 7 | The A89 through Glasgow used to be partly the A8. |
| A91 | Stirling | Zone 8 | Rerouted to bypass Stirling. Meets the A9 at Greencornhills Roundabout yet continues into Zone 8 as far as the Bannockburn Interchange. |
| A167 | Durham | Zone 6 | The A167 through Durham used to be part of the A1. |
| A168 | North Yorkshire | Zone 6 | The 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. |
| A177 | Durham | Zone 6 | In County Durham the original A1 route (now A167), not the A1(M) motorway, forms the zone boundary. |
| A181 | Durham | Zone 6 | In County Durham the original A1 route (now A167), not the A1(M) motorway, forms the zone boundary. |
| A199 | East Lothian | Zone 6 | The 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.) |
| A282 | Thurrock | Zone 1 | New 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. |
| A307 | Surrey | Zone 2 | The A307 used to be part of the A3. |
| A320 | Surrey | Zone 2 | Formerly north-east of the A3 before the Guildford Bypass. |
| A322 | Surrey | Zone 2 | Formerly north-east of the A3 before the Guildford Bypass. |
| A397 | Portsmouth | Zone 2 | The A397 used to be part of the A3. |
| A404 | Windsor and Maidenhead | Zone 3 | The 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. |
| A412 | Slough | Zone 3 | The A412 begins in Zone 3, at the A332. |
| A427 | Northamptonshire | Zone 6 | The 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. |
| A447 | Leicestershire | Zone 5 | Route south of the A47 decommissioned, leaving the remainder out-of-zone. |
| A505 | Bedfordshire | Zone 4 | The A505 was extended to become a cross-country route. |
| A601 | Derby | Zone 5 | Chosen as a unique number for the Derby inner ring road. |
| A620 | Nottinghamshire | Zone 1 | The A620 was truncated and left east of the A1. |
| A624 | Chapel-en-le-Frith, Derbyshire | Zone 5 | The A624 was part of the A6 for a short stretch in Chapel-en-le-Frith before the Chapel by-pass was built. |
| A683 | Lancashire | Zone 5 | The A683 was extended westwards to Heysham docks. |
| A689 | Cumbria | Zone 5 | The 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.) |
| A720 | Edinburgh | Zone 6 | The 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. |
| A882 | Highland | Zone 9 | The A9 was rerouted to terminate at Scrabster rather than John O'Groats, leaving the A882 in zone 9. |
| A899 | West Lothian | Zone 7 | The A899 was extended south through Livingston new town, Scotland. |
| A904 | Falkirk | Zone 8 | The A9 was rerouted to bypass Falkirk town centre. |
| A949 | Highland | Zone 8 | The A949 used to be part of the A9. |
| A1000 | Hertfordshire | Zone 6 | The A1000 used to be part of the A1. |
| A1057 | Hertfordshire | Zone 6 | The A1057 used to be part of the A1. |
| A1068 | Northumberland | Zone 6 | The A1 was rerouted around Alnwick, leaving the end of A1068 out-of-zone. |
| A1081 | Hertfordshire | Zone 6 | The A1081 used to be part of the A6. |
| A1246 | North Yorkshire | Zone 6 | The A1246 used to be part of the A1. |
| A3023 | Hampshire | Zone 2 | The A3023 was originally the B2149. |
| A3100 | Surrey | Zone 2 | The A3100 used to be part of the A3. |
| A3400 | Warwickshire | Zone 4 | The road was numbered to reflect its history as the old A34. |
| A4174 | Bristol | Zone 3 | The 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. |
| A4208 | London | Zone 3 | Truncation of the A4 left the A4208 out-of-zone. |
| A4300 | Northamptonshire | Zone 5 | The A4300 used to be part of the A43. |
| A4303 | Leicestershire | Zone 5 | The A4303 used to be part of the A427. |
| A4304 | Leicestershire | Zone 5 | The A4304 used to be part of the A427. |
| A4500 | Northamptonshire | Zone 5 | The A4500 used to be part of the A45. |
| A4501 | Northamptonshire | Zone 5 | The A4501 used to be part of the A45. |
| A5127 | Staffordshire, West Midlands | Zone 4 | The A5127 was extended south when the A38 bypassed Sutton Coldfield. The entire A5127 was part of the original route of the A38. |
| A5140 | Bedfordshire | Zone 4 | Much 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. |
| A5153 | Anglesey | Zone 4 | The A5153 lies south of the A5. |
| A5154 | Anglesey | Zone 4 | The A5154 used to be part of the A5. |
| A5223 | Telford | Zone 4 | Route begins south of the A5. |
| A6004 | Leicestershire | Zone 5 | The A6004 used to be part of the A6. |
| A6010 | Manchester | Zone 5 | The A6010 is part of the Manchester ring road. |
| A6143 | Manchester | Zone 5 | The A6143 was originally part of the A57. |
| A6144 | Trafford | Zone 5 | The A6144 used to be the B5166, B5311 and B5158. |
| A6182 | Doncaster | Zone 1 | The A1 was rerouted leaving the A6182 out-of-zone. |

## B roads

| Road number | Location | Trespassed zone | Reason |
| B197 | Hertfordshire | Zone 6 | The B197 used to be part of the A1 |
| B316 | London | Zone 4 | A4 rerouted |
| B325 | London | Zone 4 | A4 rerouted |
| B384 | West Midlands | Zone 4 | Used to be part of the A38, and numbered to match. (Initially numbered B38 by Birmingham City Council.) |
| B455 | London | Zone 3 | A4 rerouted |
| B470 | Windsor and Maidenhead | Zone 3 | |
| B576 | Northamptonshire | Zone 6 | A6 rerouted |
| B589 | Loughborough | Zone 6 | Route now runs on the wrong side of the A6. |
| B645 | Northamptonshire | Zone 5 | A6 rerouted |
| B704 | Midlothian | Zone 6 | Extends through Gorebridge whilst A7 forms western bypass. |
| B708 | West Lothian | Zone 8 | Was previously numbered as B8708 in keeping with the scheme. |
| B855 | Highland | Zone 9 | The A9 was rerouted west of this road, to end at Scrabster. |
| B876 | Highland | Zone 9 | The A9 was rerouted west of this road, to end at Scrabster. |
| B1043 | Cambridgeshire | Zone 6 | The B1043 used to be part of the A1. |
| B1164 | Nottinghamshire | Zone 6 | The B1164 used to be part of the A1. |
| B1198 | Durham | Zone 6 | In County Durham the original A1 route (now A167), not the A1(M) motorway, forms the zone boundary. |
| B1217 | Leeds | Zone 6 | extended along old A642 when M1 extended |
| B1224 | North Yorkshire | Zone 6 | In County Durham the original A1 route (now A167), not the A1(M) motorway, forms the zone boundary. |
| B1284 | Durham | Zone 6 | In County Durham the original A1 route (now A167), not the A1(M) motorway, forms the zone boundary. |
| B1350 | Edinburgh | Zone 9 | Although the B1350 is a continuation of London Road the remaining mile of the A1 is to the south at this point. |
| B2215 | Surrey | Zone 2 | The B2215 used to be part of the A3. |
| B3000 | Surrey | Zone 2 | A3 rerouted |
| B3004 | Hampshire | Zone 2 | A3 rerouted |
| B3006 | Hampshire | Zone 2 | A3 rerouted |
| B3345 | Reading | Zone 4 | A4 rerouted |
| B3800 | West Midlands | Zone 4 | The B3800 used to be part of the A4040. |
| B4640 | West Berkshire | Zone 3 | Formerly a portion of the pre-bypass A34; unknown why B4640 was chosen as it has no relation to the A34. |
| B4666 | Hinckley, Leicestershire | Zone 5 | The B4666 used to be part of the A47. |
| B4667 | Hinckley, Leicestershire | Zone 5 | The B4667 used to be part of the A447. |
| B4668 | Hinckley, Leicestershire | Zone 5 | The B4668 used to be part of the A47. |
| B4669 | Leicestershire | Zone 5 | Originally 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. |
| B5010 | East Midlands | Zone 6 | A5 rerouted |
| B5011 | Brownhills | Zone 4 | Section north of the A5 declassified, leaving the southern section out-of-zone. |
| B5061 | Shropshire | Zone 4 | A5 rerouted |
| B5070 | Wrexham | Zone 4 | The B5070 used to be part of the A5. |
| B5072 | Telford | Zone 4 | A correct zone B5072 existed in Nantwich until the 1930s. Became part of A530. |
| B5444 | Swansea | Zone 4 | Originally 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. |
| B5477 | Shropshire | Zone 4 | This 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. |
| B6000 | Derby | Zone 5 | A6 rerouted |
| B6184 | Stockport | Zone 5 | The B6184 used to be part of the B5465. |
| B6241 | Preston, Lancashire | Zone 5 | The B6241 was extended west of the A6. |
| B6280 | Darlington | Zone 1 | In County Durham the original A1 route (now A167), not the A1(M) motorway, forms the zone boundary. |
| B6291 | Durham | Zone 1 | The original section within Zone 6 was renumbered to become an extension of the A688. |
| B6420 | Nottinghamshire | Zone 1 | The A1 was re-routed, leaving its start-point out of zone. |
| B6469 | Manchester | Zone 5 | Originally numbered A57 west of the A6 and A635 to the east; probably downgraded due to construction of the A57(M). |
| B6541 | Middlesbrough | Zone 1 | The B6541 used to be part of the A66. |
| B7201 | Dumfries and Galloway | Zone 6 | The B7201 was part of the A7 before bypass of Canonbie; was B720 beforehand. |
| B8046 | West Lothian | Zone 7 | The B8046 was extended beyond both the old A8 and the M8 as far as Mid Calder, absorbing the B767. |
| B9080 | West Lothian | Zone 8 | The B9080 used to be part of the A9. |
| B9150 | Highland | Zone 8 | The B9150 used to be part of the A9. |
| B9163 | Highland | Zone 8 | A9 rerouted |
| B9164 | Highland | Zone 8 | A9 rerouted |
| B9169 | Highland | Zone 8 | A9 rerouted |
| B9176 | Highland | Zone 8 | The B9176 used to be part of the A9 |
| B9177 | Highland | Zone 8 | The B9177 used to be part of the A9 |

## Irregularities not based on the zoning system

| Road number | Location | Reason |
| A135 | Stockton-on-Tees | The other A13x roads are in southern England. |
| A139 | Stockton-on-Tees | The other A13x roads are in southern England. |
| A176 | Basildon, Essex | The other A17x roads are in North Yorkshire or County Durham. |
| A180 | Grimsby | The other A18x roads are in the North-east. The A180 is numbered as an extension of the M180. |
| A249 | Maidstone - Sheerness, Kent | The other A24x roads are in Surrey. |
| A303 | Hampshire - Somerset | The other A30x roads are in Surrey and Southwest London. |
| A403 | Avonmouth, South Gloucestershire | The other A40x roads are in or around Greater London |
| A437 | Hillingdon, Greater London | The other A43x roads are in Gloucestershire, Oxfordshire or Warwickshire. |
| A491 | Bromsgrove - Stourbridge | The other A49x roads are in North Wales. |
| A500 | Stoke-on-Trent "D"-road | The other A50x roads are in London, southern England and Northamptonshire |
| A506 | Liverpool | The other A50x roads are in London, southern England and Northamptonshire |
| A598 | Barnet, Greater London | The other A59x roads are in Cumbria (but see A594 below) |
| A720 | Edinburgh City Bypass, Edinburgh | The other A72x roads are mostly to the south and southeast of Glasgow. |
| A1018 | Tyne and Wear | The other A101x roads are in East London and Essex |
| A1300 | South Shields | The other A130x roads are in Essex and Cambridgeshire. |
| A1305 | Stockton-on-Tees | The other A130x roads are in Essex and Cambridgeshire. |
| A2022 | London & Surrey | The other A202x roads are in Sussex. |
| A2219 | Crawley | The other A220x and A221x roads are in London. |
| A2220 | Crawley | The other A220x and A221x roads are in London, (there are no other A222x roads) |
| A3031 | South London | The other A303x roads are in Southwest England. |
| A3036 | South London | The other A303x roads are in Southwest England. The route used to be the A303, before it got moved to its current route. |
| A3113 | London Heathrow Airport | The other A311x roads are on the Isles of Scilly. |
| A4010 | Buckinghamshire | The other A401x roads are in Cheltenham and Bristol. |
| A4012 | Bedfordshire | The other A401x roads are in Cheltenham and Bristol. |
| A4020 | West London | The 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. |
| A4032 | Bristol | The other A403x roads are in the West Midlands. |
| A4041 | West Midlands | The other A404x roads are in the country of Wales. |
| A4053 | Coventry Ring Road, Coventry | The other A405x roads are in the country of Wales. |
| B77 | Maybole | All other B roads in Great Britain are three or four digits. |

## Two clearly separate roads with the same number

| Road number | Locations | Locations | Locations | Notes |
| A423 | Oxford | Banbury | | The section in-between was renumbered to A4260. |
| A479 | Brecon Beacons | Wembley | | |
| A594 (Cumbria/Leicester) | Cumbria | Leicester | | The Cumbria version predates the Leicester version. |
| A728 | South Glasgow | North Glasgow | | |
| A1042 | Redcar | Norwich | | The Redcar version predates the Norwich version. |
| A1056 | Newcastle upon Tyne | Norwich | | The Newcastle version predates the Norwich version. |
| A1114 | Chelmsford | Gateshead | | |
| A1199 | Islington | Woodford | | Both are in Greater London. |
| A1243 | Great Yarmouth | Grimsby | | |
| A4102 | Amblecote | Merthyr Tydfil | | The Amblecote version predates the Merthyr Tydfil version. |
| A5028 | Seacombe | Northamptonshire | | |
| A5152 | Wrexham | Anglesey | | |
| A5271 | Stoke-on-Trent | Keswick, Cumbria | | |
| A6013 | Derbyshire | Kettering | | |
| B454 | Kingsbury, London | West London | | |
| B667 | Leicester | Thurmaston | | |
| B1140 | Norwich | Wroxham | | |
| B1172 | Spalding | Norfolk | | |
| B2122 | Surrey | Brighton | | |
| B3153 | Somerset | Weymouth | | |
| B3165 | Somerset | Surrey | | |
| B3206 | Devon | Surrey | | |
| B3330 | Winchester | Isle of Wight | | |
| B3331 | Winchester | Isle of Wight | | |
| B3440 | Weston-super-Mare | Devon | | |
| B4065 | Droitwich | Warwickshire | | |
| B4082 | Worcestershire | Coventry | | |
| B4100 | Birmingham | Oxfordshire, Warwickshire | | |
| B4104 | Meriden | Kenilworth | | |
| B4105 | Coventry | Solihull | | |
| B4118 | Birmingham | Coventry | | |
| B4122 | Birmingham | Wiltshire | | |
| B4587 | Dudley | Wiltshire | | |
| B4624 | Llandysul | Evesham | | |
| B5120 | Dunstable | Prestatyn | | |
| B5142 | Wirral | Weaverham | | |
| B5144 | Wirral | Weaverham | | |
| B5192 | Kirkby | Kirkham | Wirral | Only number that exists in three locations. |
| B5207 | Netherton | Lancashire | | |
| B5210 | Central Warrington | Warrington | | |
| B5444 | Mold | Swansea | | The Swansea version is out-of-zone. |
| B5477 | Wallasey | Church Stretton | | The Church Stretton version is out-of-zone. |
| B6135 | Drighlington | Yorkshire | | |
| B6265 | North Yorkshire | West Yorkshire | | |
| B6322 | Haltwhistle | Consett | | |
| B6374 | Roxburghshire | Derbyshire | | |
| B6452 | Galashiels | Rochdale | | |
| B9178 | Dulnain Bridge | Peterhead | | |