The M23 is a

motorway A controlled-access highway is a type of highway that has been designed for high-speed vehicular traffic, with all traffic flow—ingress and egress—regulated. Common English terms are freeway, motorway, and expressway. Other similar terms ...

in the

United Kingdom The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Northwestern Europe, off the coast of European mainland, the continental mainland. It comprises England, Scotlan ...

, running from the south of

Hooley Hooley is a village in the borough of Reigate and Banstead in Surrey, England. Within its small grid of streets is the 13th-century church of Chipstead which has been, since time immemorial, its ecclesiastical parish. Hooley is connected via pa ...

Surrey Surrey () is a Ceremonial counties of England, ceremonial county in South East England. It is bordered by Greater London to the northeast, Kent to the east, East Sussex, East and West Sussex to the south, and Hampshire and Berkshire to the wes ...

, where it splits from the A23, to

Pease Pottage Pease Pottage is a village in the Mid Sussex District of West Sussex, England. It lies on the southern edge of the Crawley built-up area, in the civil parish of Slaugham. The village has a motorway service station, named after the villag ...

, south of

Crawley Crawley () is a town and Borough status in the United Kingdom, borough in West Sussex, England. It is south of London, north of Brighton and Hove, and north-east of the county town of Chichester. Crawley covers an area of and had a populat ...

West Sussex West Sussex is a Ceremonial counties of England, ceremonial county in South East England. It is bordered by Surrey to the north, East Sussex to the east, the English Channel to the south, and Hampshire to the west. The largest settlement is Cr ...

where it rejoins the A23. The northern end of the motorway starts on what is effectively a spur north of junction 7 of the

M25 motorway The M25 or London Orbital Motorway is a major ring road encircling most of Greater London. The motorway is one of the most important roads in the UK and one of the busiest. Margaret Thatcher opened the final section in 1986, making the M25 th ...

(junction 8 on the M23). From Hooley it runs for past Redhill,

Gatwick Airport Gatwick Airport , also known as London Gatwick Airport (), is the Airports of London, secondary international airport serving London, West Sussex and Surrey. It is located near Crawley in West Sussex, south of Central London. In 2024, Gatwic ...

and Crawley. A spur runs from junction 9 to Gatwick Airport.

History

The motorway was constructed between 1972 and 1975, at the same time as the southern section of the M25 from

Godstone Godstone is a village and civil parishes in England, civil parish in the Tandridge District of Surrey, England. It is east of Reigate, west of Oxted, east of Guildford and south of London. Close to the North Downs, both the North Downs Way ...

Reigate Reigate ( ) is a town status in the United Kingdom, town in Surrey, England, around south of central London. The settlement is recorded in Domesday Book of 1086 as ''Cherchefelle'', and first appears with its modern name in the 1190s. The ea ...

(M25 junctions 6 to 8). The current northern terminus at junction 7 uses the original sliproads to meet the A23 and a flyover above the junction built for the onward northern continuation remains unused. The cancellation of the unbuilt northern section from the M25 in towards Central London has resulted in the A23 carrying the majority of traffic through South London to the motorway. This is largely a single carriageway route, with many level junctions, traffic lights and awkward interchanges. It travels largely through residential areas and is inadequate for the level of traffic it carries. A new junction (J10a) was opened in 1997, between J10 and J11, for access to the new

neighbourhood of Maidenbower. It was financed as part of the development of Maidenbower by the construction consortium. It has only a northbound slip road, no southbound access.

Unbuilt sections

The M23 was planned to relieve congestion on the A23 through

Streatham Streatham ( ) is a district in south London, England. Centred south of Charing Cross, it lies mostly within the London Borough of Lambeth, with some parts extending into the neighbouring London Borough of Wandsworth. Streatham was in Surrey ...

Thornton Heath Thornton Heath is a district of South London, England, within the London Borough of Croydon. It is around north of the town of Croydon, and south of Charing Cross. Prior to the creation of Greater London in 1965, Thornton Heath was in the Coun ...

, Purley and Coulsdon in south London and was originally intended to terminate in Streatham Vale at a junction with the controversial

London Ringways The London Ringways were a series of four ring roads planned in the 1960s to circle London at various distances from the city centre. They were part of a comprehensive scheme developed by the Greater London Council (GLC) to alleviate traffic co ...

Plan's Ringway 2 (the intended replacement of the South Circular Road (A205)). In an earlier version of the Ringways Plan it would have continued into central London where it would have met the Balham Loop spur from Ringway 1 (the London Motorway Box) at

Tooting Tooting is a district in South London, forming part of the London Borough of Wandsworth. It is located south south-west of Charing Cross. History Tooting has been settled since pre-Anglo-Saxons, Saxon times. The name is of Anglo-Saxon ori ...

. This was dropped in 1967 when the northern terminus was changed to Ringway 2. While a definite route had not been chosen at that time for the northern section, approval was met for the route south of the

Greater London Greater London is an administrative area in England, coterminous with the London region, containing most of the continuous urban area of London. It contains 33 local government districts: the 32 London boroughs, which form a Ceremonial count ...

boundary at Hooley. By 1972 the southern section of Ringway 2 had been dropped from the plan, with an alternative proposal that the M23 continue further into London to end on Ringway 1. This was immediately countered in the same year by the GLC, who announced they would not be building that Ringway, which meant that had the M23 continued north into inner London it would not have had the motorway required at its northern end to distribute traffic to the east and west. The M23 plan was gradually scaled back further to omit the section across Mitcham Common and end the motorway at an unsuitable location on Croydon Road ( A232) before the plan was postponed indefinitely. By the late 1970s, the area along the proposed line of the motorway had become affected by

blight Blight is a specific symptom affecting plants in response to infection by a pathogenic organism. Description Blight is a rapid and complete chlorosis, browning, then death of plant tissues such as leaves, branches, twigs, or floral organs. A ...

, and while the proposals were finally dropped in the mid-1980s, much of the land reserved for the route was not released by the

Department for Transport The Department for Transport (DfT) is a Departments of the Government of the United Kingdom, ministerial department of the Government of the United Kingdom. It is responsible for the English transport network and a limited number of transport ...

until the mid-1990s. The missing section of motorway and the missing six junctions north of Hooley were not constructed due to the refusal of the GLC to finance the project, having encountered large scale opposition to the construction of Ringways elsewhere in London. However, the scale of the four-tier junction between the M23 and the M25, one of only three stack interchanges in the UK, is indicative of the importance attached to the M23 at that time.

Smart motorway

Between July 2018 and July 2020 works took place to upgrade the M23 between junctions 8 and 10 to an all-lane-running motorway. The upgrades took place mostly for more reliable journeys to Gatwick Airport and increase the overall capacity of the route. The upgrades include an all-lane-running motorway, 12 new emergency areas, a new concrete central barrier replacing the current steel one, new roadside sound barriers, variable speed limits and two new emergency access slip roads. Changes were also implemented on the M23 junction 9 spur, with the hard shoulder west bound converted to a running lane, and static speed limits implemented in both directions. In January 2020 all smart motorway projects were put under review due to concerns about their safety, during this period no new smart motorways could open. The review was published on 12 March 2020 and required no immediate amendments to the design or construction, however new technology to detect static vehicles is required to be fitted within three years, and a review on spacing of emergency refuge areas was to be carried out. The fourth lane was opened to traffic on 2 April 2020, however with a temporary 50 mph speed limit. Works were scheduled to take place until July 2020 to finish installation of equipment, followed by testing and commissioning, before the project is completed and can run at the national speed limit.

Junctions

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Merstham Merstham is a town in the borough of Reigate and Banstead in Surrey, England. It lies 17 miles south of Charing Cross just beyond the Greater London border. Part of the North Downs Way runs along the northern boundary of the town. Merstham has ...

, 17.0
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Croydon Croydon is a large town in South London, England, south of Charing Cross. Part of the London Borough of Croydon, a Districts of England, local government district of Greater London; it is one of the largest commercial districts in Greater Lond ...

, Road continues as A23 to Croydon , - , 19.0
19.3 , 30.5
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''Merstham Interchange''
Merstham Interchange – Intersection of M25 and M23 , -

Heathrow Heathrow Airport , also colloquially known as London Heathrow Airport and named ''London Airport'' until 1966, is the primary and largest international airport serving London, the capital and most populous city of England and the United Kingdo ...

Watford Watford () is a town and non-metropolitan district with Borough status in the United Kingdom, borough status in Hertfordshire, England, northwest of Central London, on the banks of the River Colne, Hertfordshire, River Colne. Initially a smal ...

Dartford Crossing The Dartford–Thurrock River Crossing, commonly known as the Dartford Crossing and until 1991 the Dartford Tunnel, is a major road crossing of the River Thames in England, carrying the A282 road between Dartford in Kent in the south and Thurr ...

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Horley Horley is a town in the borough of Reigate and Banstead in Surrey, England, south of the towns of Reigate and Redhill. The county border with West Sussex is to the south with Crawley and Gatwick Airport close to the town. It has its own econ ...

, 26.5
26.8 , 42.7
43.1 , 9 , -

Gatwick Gatwick Airport , also known as London Gatwick Airport (), is the secondary international airport serving London, West Sussex and Surrey. It is located near Crawley in West Sussex, south of Central London. In 2024, Gatwick was the second-bu ...

, Redhill , Terminus of spur towards Gatwick , - , rowspan="3",

, 28.5
28.6 , 45.8
46.1 , 10 , -

East Grinstead East Grinstead () is a town in West Sussex, England, near the East Sussex, Surrey, and Kent borders, south of London, northeast of Brighton, and northeast of the county town of Chichester. Situated in the northeast corner of the county, bord ...

, , - , 30.3
30.6 , 48.8
49.2 , bgcolor=ffdddd, 10a , bgcolor=ffdddd, -

, bgcolor=ffdddd, No exit from M23 Northbound, no access to M23 Southbound , - , 33.1
33.4 , 53.3
53.8 , 11 , Pease Pottage services
-

Brighton Brighton ( ) is a seaside resort in the city status in the United Kingdom, city of Brighton and Hove, East Sussex, England, south of London. Archaeological evidence of settlement in the area dates back to the Bronze Age Britain, Bronze Age, R ...

Horsham Horsham () is a market town on the upper reaches of the River Arun on the fringe of the Weald in West Sussex, England. The town is south south-west of London, north-west of Brighton and north-east of the county town of Chichester. Nearby to ...

, Road continues as A23 to Brighton , - ;Coordinate list

In popular culture

The rivalry between Brighton & Hove Albion and Crystal Palace football clubs is often referred to as the M23 Derby. The M23 is the only motorway in Sussex.

References

External links

www.cbrd.co.uk
*
Motorway Database – M23
*
History of the aborted M23 plan
{{DEFAULTSORT:2-0023 Motorways in England Roads in Surrey Roads in West Sussex Transport in Crawley