|Location Map ( geo)
|Pease Pottage (TQ265336)
|16 miles (25.7 km)
|M25, A23, A264, A2011
|Route outline (key)
The motorway terminates at junction 7 at the northern end; it was planned to extend into London, with its terminus being on Ringway 2, the motorway replacement for the A205 South Circular Road. Only the rural section of the planned motorway was ever built, however its ambitions to be a major route in and out of London is clear by having a four lane + hard shoulder cross section on the short section between junction 7 & 8. The section of motorway between junctions 8 & 9 was proposed to be widened to four lanes in "Trunk Roads, England into the 1990s" whitepaper, however this never came about, instead the motorway between junctions 8 & 10 was upgraded to a four lane - all lanes running smart motorway in 2019-2020. There has been one new junction built since the completion of the motorway, junction 10A which only has North-facing slip roads built in 1997 as a part of a housing development in Crawley.
South of the M23 is the A23, which has now largely been upgraded to a high quality dual carriageway with three or two lanes all the way to the A27 at Brighton. Never has the M23 been officially proposed to extend beyond Crawley, but the structures along the A23 such as bridges & subways share the same datum point as the M23, despite the A23 having marker posts which count the other way from the A27. When "expressways" were first proposed it could of resulted in the A23 being upgraded to a motorway classification (either M23 or A23(M)), but the expressways plans never came to reality. In 2022 "Transport for the South East" had a "smart motorway" upgrade for the A23 between Crawley & Burgess Hill", however this didn't get past the options stage.
In the 1960s the M23 was being planned to replace parts of the "A23 London - Brighton Trunk Road". At the time the A23 already had some parts of the road widened to a two lane dual carriageway, mostly south Gatwick Airport to Bolney, with a few more sections of dual carriageway at Pyecombe. It was decided that the M23 would run from central London where it would connect onto Ringway 2 all the way to the Southern side of Crawley with an additional spur link to Gatwick Airport, this would allow the recently widened A23 to be utilised, although all of the A23 south of the M23 has since been realigned and upgraded.
The rural section of the motorway from junction 7 to 11 was first put up for construction along with the the M25 Junctions 6 to 8, which would be connected at the Merstham Interchange using a Four Level Stack junction. The first section of the M23 to open was between Junction 7 & Junction 8 which allowed access onto the M25 to and from the North, this opened in December 1974, this section of motorway opened as the A23(M). In November of 1975 the rest of the motorway was opened all the way to Junction 11, and the whole motorway was numbered M23. The Gatwick Spur was opened at a similar time.
The Urban section was never put forward for tender as by 1973 the ringways scheme was largely cancelled and would mean no suitable roads for the M23 to end at.
New Junction (10A)
In 1997 a new junction was added to the M23. This being on the South Eastern side of Crawley. This connected the motorway to Balcombe Road (B2036) and only has North-facing slip roads and was constructed as part of the "Maidenbower" neighbourhood development in Crawley.
Smart Motorway Upgrade
In 2019/2020 the M23 between junction 8 & 10 was upgraded to an all-lanes running smart motorway. This provided 4 running lanes in both directions between junction 8 & 10 by removing the hard shoulder, however there is a lane drop at junction 9 for Gatwick Airport. The merge & diverge at Junction 8 with the M25 was majorly redesigned, as the A23 north of the M23 is still a two lane single carriageway, the amount of traffic heading into London in minimal when compared to traffic leaving the M23 for the M25. Now 3 of the four lanes head to the M25, with 2 of the four lanes continuing to London. The Gatwick Spur also received some changes as the Airportbound carriageway had its hardshoulder replaced with a traffic lane, however, due to its short length it is subjected to a fixed 50mph speed limit rather than a variable speed limit. The Motorwaybound carriageway remains two lanes + hardshoulder at 70mph. Other changes that were made during the smart motorway upgrade was an additional turn around at Coopers Hill for emergency vehicles along with slip roads enlarged at the Weatherhill Highway Maintenance Depot.
Proposed highway changes at Gatwick Airport
As part of Gatwick Airport Limited (GAL) airport expansion plans there was planned changes to the M23 Gatwick Spur. Junction 9A is proposed to get a fly over - this is currently a roundabout where the M23 spur ends. In addition the Motorwaybound carraigeway which was not made all lanes running is proposed to become all-lanes running. Further the proposals suggest declassifying the spur road from a motorway to an all-purpose road, however the exact reason for this change is unclear as the spur road only leads to a motorway - comments from both National Highways & West Sussex County Council both question the need for this downgrade.
When the M23 was being planned it was planned to have two service areas. In the unbuilt Northern section a service station was proposed at Woodmansterne, on the now border of Greater London & Surrey between Junction 6 (unbuilt) & Junction 7. This service area may of catered for both the M23 & M25, hence its close proximity to the M25. In the constructed Southern section of the motorway, a service station was initially proposed at Shipley Bridge as policies at the time required a distance of services being no less than 15 miles apart. Shipley Bridge Services would be located off of Junction 9, or between Junction 9 & 10, however when it came to constructing the M23 it was decided that it was too short to warrant having a services constructed. So no services were built on M23 for its opening, or planned to open.
Pease Pottage services are located at the southern end of M23, and is one of the smallest MSAs on the British motorway network. It can be accessed off of Junction 11. The services were opened in 1988, but not as a designated "motorway service area" (MSA) until later.
The Hooley Interchange is a junction between the M23 and A23. It is also the northern terminus of the M23, although that motorway was supposed to head further north. As a result, the junction is unfinished, leaving two unused flyovers over the A23. A short section of motorway north of the junction here was shown as "under construction" on OS maps until ~2005 despite the plans of a motorway north of here had been dead for decades.
The Merstham Interchange is a Four Level Stack junction between the M25 and the M23. It is one of three four-level stacks in the United Kingdom. The junction is only a mile south of the terminus of the M23, the Hooley Interchange. Consequently, very little traffic heads north from here and only two lanes run through the junction.
The Gatwick Interchange is a Roundabout interchange junction that connects the M23 Gatwick Spur to the M23 mainline. It only provides access to the Gatwick Spur which in turn leads to Gatwick Airport, Crawley & Horley.
The Crawley Interchange is a Roundabout interchange junction that connects the A2011 & A264 to serve the towns of Crawley & East Grinstead. Initially the Junction only connected on the A2011 which was built at the same time as the M23, however in the late 1980s the Copthorne Link was built which connected the A264 to the motorway.
Balcombe Road Junction
The Balcombe Road Junction is a Half dumbbell junction that connects the M23 to the B2036 with North-facing slip roads only. It was built in 1997 to serve a new neighbourhood of Crawley.
Pease Pottage Interchange
The Pease Pottage Interchangee is a Roundabout interchange junction which is the terminus point of the M23. The route continues as the A23 south towards Brighton. From the Roundabout the A23 into Crawley, A264 Westbound & Motorway Service Area can be accessed. The A264 South Western Crawley Bypass was only completed in the 1990s & the junction received major works in 2019-20
- The M23 Motorway (Junctions 8 to 10) (Variable Speed Limits) Regulations 2020 - These Regulations introduce variable speed limits to the northbound and southbound carriageways of the M23 motorway between junctions 8 and 10 and to roads which connect with the M23 motorway at those junctions.
- The M23 Motorway (Gatwick Spur) (50 Miles Per Hour Speed Limit) Regulations 2020 - These Regulations introduce a 50 miles per hour speed limit on part of the westbound carriageway of the Gatwick Spur on the M23 motorway.
Relating to Smart Motorway
- M23 J7 Hooley Interchange (photos taken April 2004)
- M23 Abandoned/Unused Bridge (photos taken April 2004)
- Hooley Interchange (M23 J7) Revisited (photos taken May 2008)