View source for Great Britain road numbering scheme

{{short description|none}}
{{See also|Odonymy in the United Kingdom}}
{{Use British English|date=August 2023}}
{{Use dmy dates|date=August 2020}}
[[File:United Kingdom A road zones.svg|thumb|The numbering zones for A & B roads in Great Britain]]
In [[Great Britain]], there is a [[numbering scheme]] used to [[Categorization|classify]] and identify all roads. Each road is given a single letter (representing a category) and a subsequent number (between one and four digits). Though this scheme was introduced merely to simplify funding allocations, it soon became used on maps and as a method of navigation. There are two sub-schemes in use: one for [[List of motorways in the United Kingdom|motorways]], and another for non-motorway roads.

While some of Great Britain's major roads form part of the [[international E-road network]], no E-routes are signposted in the United Kingdom. Due to changes in local road designation, in some cases roads are numbered out of zone. There are also instances where two unrelated roads have been given exactly the same number; for example, the [[A594 road (Leicester)|Leicester Ring Road]] and [[A594 road (Cumbria)|a road in Cumbria]] are both designated A594.

This scheme applies only to [[England]], [[Scotland]] and [[Wales]]; a separate system using similar conventions is used in [[Roads in Northern Ireland|Northern Ireland]], as well as outside the United Kingdom in the [[Roads in the Isle of Man|Isle of Man]], [[Roads in Jersey|Jersey]] and [[British Overseas Territories]].

== History ==
Work on classification began in 1913. The Road Board had been established in 1909 to administer [[Vehicle Excise Duty]]<ref>{{cite book |last1=Daunton|first1= Martin J|title= Just Taxes: The Politics of Taxation in Britain, 1914–1979|year= 2002|publisher= [[Cambridge University Press]]|location= England|isbn= 0-521-81400-6}}</ref> - money raised by taxation to pay for new road construction and for repair of damage done to existing roads by the growing number of motorists.<ref name=Reid30>{{cite book |last1=Reid |first1=Carlton |title=Roads Were Not Built For Cars |date=2014 |publisher=Red Kite Prayer/Front Page Creations |location=Newcastle |isbn=9780993005701}} p.30.</ref> As the Board needed to work out which roads should be funded, upgraded or replaced, its secretary, [[William Rees Jeffreys]], appointed [[Henry Maybury]], one of the Board's senior engineers, to devise a classification system and then assign numbers to the highways for identification purposes.<ref name="RdNos">{{cite web |title=Road numbers: how it happened |url=https://www.roads.org.uk/articles/road-numbers/how-it-happened |website=Roads.org.uk |access-date=18 March 2022}}</ref> The work was interrupted by the [[First World War]].{{cn|date=September 2024}} It did not resume until the [[Department for Transport|Ministry of Transport]] was formed in 1919 and given authority to classify highways<ref name="dftfoi20050805">{{cite web |url=http://www.dft.gov.uk/foi/responses/2005/aug/roadnumbering/etteraboutroadclassification.pdf |archive-url=http://webarchive.nationalarchives.gov.uk/20090512074359/http://www.dft.gov.uk/foi/responses/2005/aug/roadnumbering/etteraboutroadclassification.pdf |url-status=dead |archive-date=2009-05-12|title=FOI Request – Road numbering |publisher=Department for Transport |date=2005-08-05 |access-date=2007-12-27}}</ref> and to allocate funding for road maintenance, authority for which was granted by section 17 (2) of the [[Ministry of Transport Act 1919]].{{cn|date=September 2024}} A classification system was created in 1922,<ref name="nathigh">{{cite web |title=History of roads and National Highways |date=15 April 2020 |url=https://nationalhighways.co.uk/about-us/history-of-roads-and-national-highways/ |publisher=National Highways |access-date=23 December 2022}}</ref> under which important routes connecting large population centres, or for through traffic, were designated as Class I, and roads of lesser importance were designated as Class II. The definitive list of those roads was published on 1 April 1923, following consultations with [[local authorities]].<ref name="1922roadslist">{{cite web|url=http://www.sabre-roads.org.uk/wiki/index.php?title=1922_Road_Lists |title=List of Class I and Class II Roads and Numbers (transcription)|work=HMSO and National Archives files MT39/241 and MT39/246}}</ref>{{Unreliable source?|date=June 2011}}{{cn|date=September 2024}} Government funding towards the repairs of these roads were set at 60% for the former and 50% for the latter.<ref>{{cite book |first2=Ron|last2= Bridle |first1=John |last1=Porter |title=The Motorway Achievement |year=2002 |publisher=Thomas Telford |isbn=0-7277-3196-3 |pages=27}}</ref>

Shortly after this, the numbers started to appear in road atlases and on signs on the roads themselves, making them a tool for motorists{{cn|date=September 2024}} in addition to their use for determining funding. The numbers of the roads changed quite frequently during the early years of the system, because it was a period of rapid expansion of the network and some numbered routes did not follow the most usual routes taken.<ref name="1920srenumbering">{{Cite web|url=https://www.sabre-roads.org.uk/wiki/?title=Sandbox:_1920s_Renumbering|title=Sandbox: 1920s Renumbering - Roader's Digest: The SABRE Wiki|website=www.sabre-roads.org.uk}}</ref> The [[Trunk Roads Act 1936]] gave the Ministry direct control of major routes and a new classification system was created to identify these routes. Originally, those numbers beginning in T were to be made public, but that was eventually deemed unnecessary.{{cn|date=September 2024}}

With the introduction of motorways in the late 1950s, a new classification of "M" was introduced. In many cases the motorways duplicated existing stretches of A road, which therefore lost much of their significance and were in some cases renumbered. There was no consistent approach to the renumbering – some A roads retained their existing number as non-primary roads (e.g. the [[A40 road|A40]] running alongside the [[M40 motorway|M40]]), others were given "less significant" numbers (e.g. the [[A34 road (England)|A34]] in Warwickshire became the A3400 after the M40 was built), and the remainder were downgraded to B or unclassified roads (e.g. the [[A38 road|A38]], which was replaced by the [[M5 motorway|M5]] between [[Tiverton, Devon|Tiverton]] and [[Exeter]]).{{Specify|date=December 2007}} Occasionally, the new motorway would take the name of the old A road rather than having its own number. The most notable example of that is the [[A1(M)]].

== Zoning system ==
[[File:Crouch Hill - geograph.org.uk - 1600248.jpg|thumb|This sign at Crouch Hill shows two road numbers in Zone 2.]]

=== Non-motorway ===
In England and Wales the road numbering system for all-purpose (i.e. non-motorway) roads is based on a radial pattern centred on [[London]]. In Scotland the same scheme is centred on [[Edinburgh]]. In both cases the main single-digit roads normally define the zone boundaries.{{cn|date=September 2024}} The exception is between Zones 1 and 2, where the [[River Thames]] defines the boundary so that all of Kent is in 
Zone 2.{{cn|date=September 2024}}

* Zone 1: North of the [[River Thames|Thames]], east of the A1 covering much of [[Greater London|North London]], [[Essex]], [[Cambridgeshire]], [[East Anglia]], [[Lincolnshire]], parts of [[Yorkshire]], [[County Durham]], [[Tyne and Wear]], [[Northumberland]], parts of the [[Scottish Borders]], [[East Lothian]] and on up to [[Edinburgh]]
* Zone 2: South of the [[River Thames|Thames]], east of the A3 covering most of [[Greater London|South London]], part of [[Surrey]], [[Sussex]] and [[Kent]]
* Zone 3: North/West of the A3, south of the A4 covering part of Surrey, [[Hampshire]] (excluding [[Portsmouth]]), the [[Isle of Wight]] and [[South West England]]
* Zone 4: North of the A4, south/west of the A5 covering the [[South Midlands|south]] and [[West Midlands (region)|West Midlands]], [[Oxfordshire]], [[Bristol]], [[Gloucestershire]], [[Buckinghamshire]] and [[South Wales|south]], [[West Wales|west]] and [[Mid Wales]].
* Zone 5: North/East of the A5, west of the A6, south of the [[Solway Firth]]/[[Eden Estuary]] covering [[North Wales]], North [[English Midlands|Midlands]], western [[Leicestershire]], [[Cheshire]], [[Cumbria]] and western [[Lancashire]]. In Central London, the A40 (Holborn Viaduct, Holborn, High Holborn and Oxford Street) provides a border between the 4 and 5 zones east of Marble Arch. The original A5 (now renumbered A5183) also provides such a border, and north of St Albans the original A6 (now renumbered A1081) provides an Eastern border.
* Zone 6: East of the A6 and A7, west of the A1 covering eastern [[Lancashire]], [[North East England]], [[Yorkshire]], [[Nottinghamshire]], eastern [[Leicestershire]] and [[Rutland]], and the [[Scottish Borders]] and [[Lothians]]. Between St Albans and Luton, the original A6 (now renumbered A1081) provides the Western border of the 6-zone.
* Zone 7: North of the Solway Firth/Eden Estuary, west of the A7, south of the A8 covering [[Dumfries and Galloway]], [[Ayrshire]] and [[Central Belt|Central Scotland]], including [[Glasgow]] south of the [[River Clyde|Clyde]].
* Zone 8: North of the A8, west of the A9 covering northern Glasgow, [[Argyll and Bute]], [[Highland (council area)|Highland]] and the [[Western Isles]]
* Zone 9: North of the A8, east of the A9 covering [[Fife]], [[North East Scotland (Scottish Parliament electoral region)|North East Scotland]], [[Orkney]] and [[Shetland]]

The first digit in the number of any road should be the number of the furthest-anticlockwise zone entered by that road. For example, the [[A38 road]], a [[trunk road]] running from [[Bodmin]] to [[Mansfield]] starts in Zone 3, and is therefore numbered with an A3x number, even though it passes through Zones 4 and 5 to end in Zone 6. Additionally, the A1 in [[Newcastle upon Tyne]] has moved twice. Originally along the Great North Road, it then moved to the [[Tyne Tunnel]], causing some of the roads in Zone 1 to lie in Zone 6. The designated A1 later moved to the western bypass around the city, and roads between the two found themselves back in Zone 1. For the most part the roads affected retained their original numbers throughout.

Elsewhere when single-digit roads were bypassed, roads were often re-numbered in keeping with the original zone boundaries.{{cn|date=September 2024}}

A few roads are [[Anomalously numbered roads in Great Britain|anomalously numbered]].

=== Motorways ===
{{main|List of motorways in the United Kingdom}}

[[File:Motorway number zones in England and Wales map.svg|thumb|Motorway number zones of England and Wales]]
[[Motorways]] first came to Britain over three decades after the advent of the A-road numbering event, and as a result required a new numbering system. They were given an M prefix, and in England and Wales a numbering system of their own not coterminous with that of the A-road network, though based on the same principle of zones.{{cn|date=September 2024}} Running clockwise from the [[M1 motorway|M1]] the zones were defined for Zones 1 to 4 based on the proposed [[M2 motorway (Great Britain)|M2]], [[M3 motorway (Great Britain)|M3]] and [[M4 motorway]]s. The [[M5 motorway|M5]] and [[M6 motorway|M6]] numbers were reserved for the other two planned long distance motorways.{{cn|date=September 2024}} The [[Preston Bypass]], the UK's first motorway section, should have been numbered A6(M) under the scheme decided upon, but it was decided to keep the number M6 as had already been applied.{{cn|date=September 2024}} The first full-length motorway in the UK was the [[M1 motorway]].

Shorter motorways typically take their numbers from a parent motorway in contravention of the zone system, explaining the [[Anomalously numbered roads in Great Britain|apparently anomalous numbers]] of the [[M48 motorway|M48]] and [[M49 motorway|M49]] motorways as [[spur route|spurs]] of the M4, and [[M271 motorway|M271]] and [[M275 motorway|M275]] motorways as those of the [[M27 motorway|M27]].{{cn|date=September 2024}}
This numbering system was devised in 1958–59 by the then [[Department for Transport|Ministry of Transport and Civil Aviation]], and applied only in England and Wales. It was decided to reserve the numbers 7, 8 & 9 for Scotland.{{cn|date=September 2024}} In Scotland, where roads were the responsibility of the [[Scottish Office]] (Scottish Government after 1999), the decision was taken to adopt a scheme whereby motorways took the numbers of the all-purpose routes they replaced. As a result, there is no M7 (as no motorway follows the [[A7 road (Great Britain)|A7]]), and when the [[A90 road|A90]] was re-routed to replace the [[A85 road|A85]] south of [[Perth, Scotland|Perth]], the short M85 became part of the [[M90 motorway|M90]].{{cn|date=September 2024}}

== A roads ==
=== Single-digit A roads ===
In England and Wales, the six single-digit numbers reflect the traditionally most important radial routes coming out of [[London]], Starting with the [[A1 road (Great Britain)|A1]] which heads due north, numbers were allocated sequentially in a clockwise direction, thus:{{cn|date=September 2024}}
* [[A1 road (Great Britain)|A1]] London to [[Edinburgh]] (also known as the Great North Road), most of the road is bypassed by the [[M1 motorway|M1]] and many sections have been upgraded to [[A1(M) motorway|A1(M)]].
* [[A2 road (Great Britain)|A2]] London to [[Dover]] (the southern part of Watling Street, also known as the Dover Road).
* [[A3 road|A3]] London to [[Portsmouth]] (also known as the Portsmouth Road).
* [[A4 road (Great Britain)|A4]] London to [[Avonmouth]] (also known as the Great West Road or the Bath Road), although this route is not used as a long-distance road since the completion of the [[M4 motorway|M4]].
* [[A5 road (Great Britain)|A5]] London to [[Holyhead]] (the Northern part of Watling Street).
* [[A6 road (Great Britain)|A6]] [[Luton]] to [[Carlisle, Cumbria|Carlisle]] (The A6 originally started in Barnet on the old A1. When the A1 was moved onto the Barnet Bypass in the 1950s, the A6 was cut back to the A1/A1(M) junction (later A1/M25 junction). Further renumbering in the St Albans area means that it now starts in Luton town centre. The old route is numbered as A1081).{{Specify|date=December 2007}}

Similarly, in Scotland, important roads radiating from Edinburgh have single-digit numbers, thus:
* [[A7 road (Great Britain)|A7]] [[Edinburgh]] to [[Carlisle, Cumbria|Carlisle]], although the [[A74(M) and M74 motorways|M74]] and [[M8 motorway (Scotland)|M8]] motorways now form the primary link.
* [[A8 road (Great Britain)|A8]] Edinburgh to [[Greenock]], which formerly linked Edinburgh to [[Glasgow]], now has a {{Convert | 25 | mi | adj = on}} gap, where it is replaced by the [[M8 motorway (Scotland)|M8]].
* [[A9 road (Great Britain)|A9]] [[Falkirk]] to [[Scrabster]]. Originally Edinburgh to [[Inverness]], the A9 was extended to [[John o' Groats]] via [[Wick, Highland|Wick]] on 16 May 1935, and later cut back at the southern end because of the construction of the main runway at [[Edinburgh Airport]] on top of it. As such, the route from Edinburgh is now replaced by the [[M9 motorway (Scotland)|M9]] (with the [[M90 motorway|M90]] across the [[Queensferry Crossing]] as an alternative to [[Perth, Scotland|Perth]]). On 1 April 1997, the A9 was diverted to [[Thurso]] and Scrabster at the northern end.

While these routes remain the basis for the numbering of the A road network, they are no longer necessarily major roads, having been bypassed by motorways or other changes to the road network.

=== Other A roads ===
These radials are supplemented by two-digit codes which are routes that ''may'' be slightly less important, but may still be classified as trunk routes, although many of these routes have lost a lot of their significance due to motorway bypasses, or the upgrading of other A-roads (such as the [[A38(M) motorway|A38 (M)]]). These routes are not all centred on London, but as far as possible follow the general principle that their number locates them radially clockwise from the associated single digit route.{{cn|date=September 2024}} For example, the [[A10 road (England)|A10]] (London to King's Lynn) is the first main route clockwise from the A1, the [[A11 road (England)|A11]] (London to Norwich) is the next, then the [[A12 road (England)|A12]] (London to Lowestoft) and the [[A13 road (England)|A13]] (London to Shoeburyness); the next radial is the [[A2 road (Great Britain)|A2]], followed by the [[A20 road (England)|A20]] (London to Dover), and so on. These roads have been numbered either outwards from or clockwise around their respective hubs, depending on their alignment.{{Specify|date=December 2007}}

The system continues to three and four digit numbers which further split and criss-cross the radials. Lower numbers originate closer to London than higher numbered ones.{{Specify|date=December 2007}} As roads have been improved since the scheme commenced, some roads with 3 or 4 digit numbers have increased in significance, for example the [[A127 road|A127]], [[A1079 road|A1079]] and [[A414 road|A414]].{{Specify|date=December 2007}} New routes have also been allocated 3 or 4 digit numbers, for example the Edinburgh City Bypass is the [[A720 road|A720]].

The [[Major Road Network]] is a proposed classification of major local-authority controlled A roads that the government committed to implementing in 2017, with the aim of better targeting road funding.<ref>{{cite web|title=Proposals for the Creation of a Major Road Network: Consultation|url=https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/670527/major-road-network-consultation.pdf|publisher=Department for Transport|access-date=5 February 2018}}</ref>

=== Lists of A roads ===
*[[A roads in Zone 1 of the Great Britain numbering scheme|Zone 1 A roads]]
*[[A roads in Zone 2 of the Great Britain numbering scheme|Zone 2 A roads]]
*[[A roads in Zone 3 of the Great Britain numbering scheme|Zone 3 A roads]]
*[[A roads in Zone 4 of the Great Britain numbering scheme|Zone 4 A roads]]
*[[A roads in Zone 5 of the Great Britain numbering scheme|Zone 5 A roads]]
*[[A roads in Zone 6 of the Great Britain numbering scheme|Zone 6 A roads]]
*[[A roads in Zone 7 of the Great Britain numbering scheme|Zone 7 A roads]]
*[[A roads in Zone 8 of the Great Britain numbering scheme|Zone 8 A roads]]
*[[A roads in Zone 9 of the Great Britain numbering scheme|Zone 9 A roads]]

=== Trunk roads and primary routes ===
{{see also|Trunk roads in Wales}}
Some A roads are designated [[trunk roads]], which implies that central government rather than local government has responsibility for them. A more recent classification is that of [[primary route]]s, the category of recommended routes for long-distance traffic. Primary routes include both trunk and non-trunk roads.

=== Motorway sections ===
Some sections of A roads have been improved to the same standard as motorways, but do not completely replace the existing road; they form a higher standard part of the route for those which are not excluded.{{cn|date=September 2024}} These sections retain the same number but are suffixed with (M), for example the [[A1 road (Great Britain)|A1(M)]] and [[A404(M) motorway|A404(M)]].{{cn|date=September 2024}} There have been occasions where this designation has been used to indicate motorway bypasses of an existing road, but the original retains the A road designation, for example [[A3 road#A3(M)|A3(M)]], [[A329(M) motorway|A329(M)]], [[A38(M)]], [[A48(M) motorway|A48(M)]] and [[A627(M) motorway|A627(M)]].{{cn|date=September 2024}}

== B roads ==

'''B roads''' are numbered [[collector road|distributor roads]], which have lower traffic densities than the main trunk roads, or A roads.  This classification has nothing to do with the width or quality of the physical road, and B roads can range from dual carriageways to single track roads with passing places. B roads follow the same numbering scheme as A roads, but almost always have 3- and 4-digit designations.{{cn|date=September 2024}} Many 3-digit B roads outside the [[London]] area are former A roads which have been downgraded owing to new road construction; others may link smaller settlements to A roads.

=== B roads in Devon ===
B roads in the county of Devon have further sub-classifications according to their accessibility.<ref>{{cite web|url=https://www.roads.org.uk/blog/devon-help-us|title=Devon help us|work=www.roads.org.uk}}</ref> This is due to the rural nature of Devon's topology making some roads unsuitable for certain types of vehicle.

The classification is denoted by the colour of the sign border and direction arrow, and can be summarised as follows:
* '''Blue''' - roads suitable for cars, minibuses and light goods vehicles excluding caravans
* '''Brown''' - roads that are only suitable for cars and other light traffic
* '''White''' - roads recommended for local traffic only

=== Lists of B roads ===
[[File:C32 Rare C road sign in Ribblesdale - geograph.org.uk - 260339.jpg|thumb|C road sign in Ribblesdale, North Yorkshire]]
*[[B roads in Zone 1 of the Great Britain numbering scheme|Zone 1 B roads]]
*[[B roads in Zone 2 of the Great Britain numbering scheme|Zone 2 B roads]]
*[[B roads in Zone 3 of the Great Britain numbering scheme|Zone 3 B roads]]
*[[B roads in Zone 4 of the Great Britain numbering scheme|Zone 4 B roads]]
*[[B roads in Zone 5 of the Great Britain numbering scheme|Zone 5 B roads]]
*[[B roads in Zone 6 of the Great Britain numbering scheme|Zone 6 B roads]]
*[[B roads in Zone 7 of the Great Britain numbering scheme|Zone 7 B roads]]
*[[B roads in Zone 8 of the Great Britain numbering scheme|Zone 8 B roads]]
*[[B roads in Zone 9 of the Great Britain numbering scheme|Zone 9 B roads]]

== Other classifications ==

=== Unclassified roads ===
Roads and lanes with yet lower traffic densities are designated as ''unclassified'' roads commonly using '''C''', '''D''' and '''U''' prefixes but, while these are numbered, in general this is done for use by the local authorities who are responsible for maintaining them and the non-unique numbering is in a local series which usually does not appear on road signs;{{cn|date=September 2024}} use of local numbers on signs in England is "not advised".<ref>{{Cite web|url=https://www.gov.uk/government/publications/guidance-on-road-classification-and-the-primary-route-network/guidance-on-road-classification-and-the-primary-route-network|title=DfT - Guidance on Road Classification and the Primary Route Network}}</ref> Exceptions to this are known in the forms of numbers on signs{{cn|date=September 2024}} and past use of prefixes '''H''' and '''V''' on signs in [[Milton Keynes]] where [[Milton Keynes grid road system|main roads have a regular grid system]].  These designations are used when [[Town and country planning in the United Kingdom|planning officers]] deal with certain [[Planning permission|planning applications]], including the creation of a new vehicular access onto a highway. The letter '''Q''' is used for many important unclassified roads in [[Fife]].

===Cycleways===
In London, [[List of cycle routes in London|Cycleways]] are using the '''C''' prefix and marked using pale green signs. There are also some '''CS''' prefixes for Cycle Superhighways, marked using magenta signs, but these are being phased out.

=== E-roads ===
Despite numerous large roads in Great Britain being part of the [[International E-road network]], no road that forms part of this network is signposted as such and only the road's national designation is shown. The same is true in Northern Ireland.

== References ==
{{reflist|30em}}

== Further reading ==
* {{cite book |last=Bancroft |first=Peter |author2=Andrew Emmerson |title=A, B, C and M: Road Numbering Revealed |date=May 2007 |publisher=Capital Transport Publishing |isbn=978-1-85414-307-5}}

== External links ==
{{Commons category|Roads in the United Kingdom}}
* [http://pathetic.org.uk/features/numbering/ Pathetic Motorways – How the motorways were numbered]
* [https://www.roads.org.uk/articles/road-numbers roads.org.uk - Road Numbering]

{{UK road lists}}

[[Category:Roads in the United Kingdom|Numbering]]