View source for M20 motorway

{{short description|Motorway in Kent, England}}
{{about|the motorway in England|the motorway in the Republic of Ireland|N20 road (Ireland)}}
{{Use British English|date=August 2025}}
{{Use dmy dates|date=August 2025}}
{{infobox road
|country=GBR
|type=M
|route=20
|e-road={{Jct|country=EUR|E|15}}
|maint=[[National Highways]]
|length_mi=50.6
|direction_a=West
|terminus_a=[[Swanley]]
|counties= [[Kent]]
|destinations= [[London]]<br>[[Maidstone]]<br> [[Ashford, Kent|Ashford]]<br> [[Channel Tunnel]]<br>[[Folkestone]]
|direction_b=East
|terminus_b=[[Folkestone]]
|established=1971
|history=Opened: 1960 (as [[A20 road (England)|A20]](M))<br>Renumbered: 1971<br>Completed: 1991
|junction=[[File:Junction 1.svg|1000x20px]] [[File:UK-Motorway-M25.svg|1000x20px]]<br />J1 → [[M25 motorway]]<br />[[File:Junction 3.svg|1000x20px]] [[File:UK-Motorway-M26.svg|1000x20px]]<br />J3 → [[M26 motorway]]
|map={{maplink-road|from=M20 motorway.map}}
|map_custom=yes
|map_notes=M20 highlighted in blue
|image=M20, Aylesford, Kent - geograph.org.uk - 190820.jpg
|image_notes=Looking east near [[Aylesford]], 2006
|previous_type = M
|next_type = M
|previous_route = 18
|next_route = 23
}}
The '''M20''' is a [[Controlled-access highway|motorway]] in [[Kent]], England. It follows on from the [[A20 road (England)|A20]] at [[Swanley]], meeting the [[M25 motorway|M25]], and continuing on to [[Folkestone]], providing a link to the [[Channel Tunnel]] and the ports at [[Dover]]. It is {{convert|50.6|mi|km}} long. Although not signposted in England, this road is part of the [[European route E15]]. It is also used as a holding area for goods traffic when traffic across the [[English Channel]] is disrupted, such as [[Operation Stack]] and [[Operation Brock]].

==Route==
The road starts at its junction with the [[M25 motorway]] and [[A20 road (England)|A20 road]] just east of [[Swanley]], then continues south east across the [[River Darent]], north of [[Farningham]] through the [[North Downs]], past [[West Kingsdown]] and [[Wrotham]] where the [[M26 motorway|M26]] merges with it. It then strikes east, running north of [[Addington, Kent|Addington]]. After it reaches junction 4 it passes south of [[New Hythe]] and runs parallel to the [[Medway Valley Line|Medway Valley railway line]] before crossing it close to junction 5. This next section was the old [[Maidstone]] [[Bypass (road)|bypass]]. The [[High Speed 1]] (HS1) railway line then runs parallel to the motorway as it continues to the north of [[Bearsted]], crosses the [[Maidstone line|Swanley to Ashford (via Maidstone East) line]] then out into the [[countryside]] north of [[Leeds Castle]]. Proceeding south of [[Lenham]] and [[Charing]] it is crossed by the Ashford and HS1 railway lines before becoming the [[Ashford, Kent|Ashford]] bypass.  Travelling past [[Brabourne Lees]] it is once again joined by HS1 and the [[East Stour, Kent|East Stour]].

Just north of [[Saltwood]] it reaches the Channel Tunnel terminal and is crossed by HS1 for the last time. The final section runs along the northern [[suburb]]s of Folkestone, giving access to the A20 to Dover.

==History==

===Construction===
The M20 was, in common with many United Kingdom motorways, opened in stages:<ref>{{cite web|url=http://www.iht.org/motorway/m20lofostat.htm |title=The Motorway Archive – M20 Dates |publisher=Iht.org |access-date=31 December 2011}}</ref>

Junctions 5 to 7 (the old Maidstone By-Pass) first opened in 1960. The road was then being extended east, to the site of the 'Old England' pub on the A20 at [[Hollingbourne]] Corner, which became junction 8, a temporary terminus until 1992. It would cost £1.5{{nbsp}}million for the eastern section {{convert|5.25|mi|1}} to open by the end of March 1960, built by Costain, designed by Scott Wilson.<ref>''Kentish Express'' Friday 28 March 1958, page 1</ref> Work was initiated on the Bearsted by-pass section from Hollingbourne on Monday 5 May 1958 by [[Richard Nugent, Baron Nugent of Guildford]], this was only five weeks after the M1 had started. It was one of three main motorway / by-pass projects started in 1958.<ref>''East Kent Gazette'' Friday 9 May 1958, page 6</ref><ref>''Kentish Express'' Friday 9 May 1958, page 1</ref> The section was intended to open on 27 March 1960, but was late. On Wednesday 1 June 1960, {{convert|5|mi}} was opened at Forstal (A229) (junction 5) by Sir Leslie Doubleday, chairman of Kent County Council.<ref>''Kentish Express'' Friday 3 June 1960, page 1</ref> Maidstone already had a narrow by-pass road, no more than a rural lane  crossing the Medway by the medieval bridge at Aylesford {{ndash}} then numbered the A2011, which largely followed the line of the A20(M) bypass. There followed a short section of the A20(M) west of the A229 with a temporary terminus on the A2011 at the A20 near Preston Hall (British Legion Village).

Junctions 7 to 8 fully opened in 1961. It was {{convert|1.5|mi}}, to take 15{{nbsp}}months, planned for October 1960. The contract of £822,928 in March 1959 was given to Sir Robert McAlpine.<ref>''The Scotsman'' Monday 16 March 1959, page 3</ref><ref>''Times'' Monday 16 March 1959, page 19</ref> Piles were constructed by West's Piling & Construction, of [[Harmondsworth]]. Work was started on Monday 13 April 1959 by Harold Watkinson near Cobtree Manor.<ref>''Nottingham Guardian'' Tuesday 14 April 1959, page 2</ref> The bridge across the  Medway cost £200,000. The section opened on 3 December 1960. Coldharbour Lane temporary junction was widened to {{convert|33|ft}}, with a roundabout on the A20, with a terminus of the A20(M) {{convert|0.5|mi}} north along Coldharbour Lane (junction 5). It was the south of England's first motorway.<ref>''Kent & Sussex Courier'' Friday 9 December 1960, page 14</ref>

These sections of the M20 were known as the 'Maidstone Bypass'. This road was then numbered as the A20(M) as it bypassed the stretch of A20 through Maidstone town centre which was renumbered [[A2020 road|A2020]].{{cn|date=September 2024}} This was the first stretch of motorway to open south of London.{{cn|date=September 2024}} Plans for a bypass of Maidstone had existed since the 1930s, originally as an all-purpose project, before being upgraded to motorway standard in the 1950s.<ref>{{citation|id=MT39/465|title=Motorways: Maidstone By-Pass (Motorway)|publisher=The National Archives|date=1934–1954}}</ref> When the motorway was extended westwards towards London in the 1970s, it was renamed M20 and the A2020 reverted to A20.
*Junctions 3 to 5 were opened in 1971
*Junctions 1 to 2 were opened in 1977, the West Kingsdown to Addington section {{convert|7|mi}}. It was constructed by Dowsett, with project manager Keith Haddock. The good weather in 1976 had helped<ref>''Kentish Advertiser'' Saturday 20 October 1979, page 1</ref>
:This section ended at a temporary junction near West Kingsdown.<ref name="harms">{{cite web |url=http://www.highways.gov.uk/roads/projects/6690.aspx |title=Highways Agency – M20/M26/A20(London – Dover) Route Management Strategy |publisher=Highways.gov.uk |access-date=31 December 2011 |archive-url=https://web.archive.org/web/20070927223343/http://www.highways.gov.uk/roads/projects/6690.aspx |archive-date=27 September 2007 |url-status=dead }}</ref>
*Temporary terminus to junction 3 in 1980 {{ndash}} this section of the route was difficult to construct due to its steep descent down the North Downs escarpment.{{citation needed|date=December 2012}}
*Sellindge to junction 13 in 1981 {{ndash}} constructed by McAlpines
*Junction 9 to Sellindge in 1981 {{ndash}} constructed by Dowsett

The section around Ashford (junctions 9–10) was originally the A20 Ashford Bypass with actual construction having started before World War 2 – although the route itself was not opened until 19 July 1957.<ref>{{cite web|url=https://api.parliament.uk/historic-hansard/commons/1957/jul/22/roads-programme#S5CV0574P0_19570722_HOC_300|title=Hansard|date=22 July 1957|work=[[Hansard|Parliamentary Debates (Hansard)]]|access-date=18 October 2011}}</ref> The bypass started at Willesborough near the current location of junction 10 and terminated south of the existing junction 9 at the current Drover's Roundabout. A section of the old bypass is still visible now named Simone Weil Avenue. The original bridge that brought Canterbury Road over the bypass is still visible as the bridge was not reconstructed when the motorway was constructed. This section of motorway has no hard shoulder indicating the smaller width of the old bypass.

This left the motorway in two sections, with the {{convert|14|mi|km|adj=on}} gap running via the A20 {{ndash}} this was referred to locally as 'The Missing Link'.<ref>{{cite web|author=Louise Stewart |url=https://www.bbc.co.uk/kent/history/history/weeklyfacts20.shtml |archive-url=https://web.archive.org/web/20030804002757/http://www.bbc.co.uk/kent/history/history/weeklyfacts20.shtml |url-status=dead |archive-date=4 August 2003 |title=BBC Kent History – This Week in Time |publisher=BBC|date=20 December 2011 |access-date=31 December 2011}}</ref> The level of traffic was not considered necessary to complete the route.  Most of the traffic for the [[English Channel|Channel]] ports was using the [[A2 road (Great Britain)|A2]]/[[M2 motorway (Great Britain)|M2]] route. When the [[Channel Tunnel]] was ready for construction, it was decided to complete the M20 between junctions 8 and 9 and this opened in 1991.  Concurrent to this was the extension to Dover as part of the A20 which opened in 1993.<ref name="harms" /> A new junction 11A was also constructed to serve the Channel Tunnel.

===Operation===
[[File:M20westCobtree.jpg|thumb|M20 near Maidstone showing separated distributor roads]]Following completion of the junction 8 to 9 section, the M20 was three lanes either side of the original A20(M) section.  This was a [[Bottleneck (traffic)|bottleneck]], so it was decided to widen this section of motorway.  The road here was increased to a dual three- or four-lane road with two-lane [[Local-express lanes|distributor roads]] either side. This section was opened in 1995.<ref name="harms" />

To the north of Maidstone, there is an overlap between the slip roads for junctions 5 (A20) and 6 (A229).

Between 2006 and 2007, junction 10 near Ashford was remodelled to increase capacity when the bridges across the motorway were modified to provide three lanes of traffic at the roundabout, and local approach roads were widened, with new traffic lights to control traffic flows at the junction between the A292 Hythe Road and the London-bound M20 entry slip road. A new footbridge was also constructed across the motorway.<ref>{{cite web|url=http://www.highways.gov.uk/roads/projects/5703.aspx|title=Highways Agency Junction 10 Interim Improvement Scheme Page}}</ref> The cost was £4.9 million.<ref>{{cite web|url=http://www.gnn.gov.uk/imagelibrary/detail.asp?MediaDetailsID=175668|title=Government News Network Press Release|date=7 September 2006}}</ref>

A [[Smart motorway|Controlled motorway]] scheme was introduced in West Kent between junctions 4 and 7, with variable speed limits.<ref>{{cite web|url=http://www.highways.gov.uk/roads/projects/18495.aspx |title=M20 Junctions 4 – 7 Controlled Motorways |publisher=Highways Agency |url-status=bot: unknown |archive-url=http://webarchive.nationalarchives.gov.uk/20120810121037/http://www.highways.gov.uk/roads/projects/18495.aspx |archive-date=10 August 2012 }}</ref>

In August 2016, part of a pedestrian footbridge connecting areas of Ryarsh divided by the motorway was brought down {{ndash}} initially suspected to be the result of an impact by a digger from nearby works to widen the southbound bridge at junction 4 being carried on a low-loader that was moving along the hard shoulder.<ref>{{cite news|url=https://www.bbc.co.uk/news/uk-england-kent-37204050|title=M20 motorway shut after lorry crash causes bridge collapse|work=BBC News|date=27 August 2016|access-date=4 September 2016}}</ref> In the incident, the southern section of the bridge {{ndash}} which rested on a plinth south of the motorway and the [[cantilever]]ed northern section{{cn|date=September 2024}} {{ndash}} was dislodged and fell onto the carriageway below, landing on the trailer of a passing HGV and being narrowly avoided by a motorcyclist who suffered broken ribs taking avoiding action.<ref>{{cite news|url=https://www.bbc.co.uk/news/uk-england-kent-37224187|title=M20 bridge collapse: Injured biker, 73, recalls 'chaos'|work=BBC News|date=30 August 2016|access-date=4 September 2016}}</ref><ref>{{cite news|url=https://www.bbc.co.uk/news/uk-england-kent-37249668|title=Collapsed M20 motorway footbridge to be removed|work=BBC News|date=September 2016|access-date=4 September 2016}}</ref> Both carriageways of the motorway were closed to enable the removal of the broken section. The motorway reopened with the Highways Agency having declared that the northern part of the bridge was structurally intact. However this section of the motorway was again closed on the weekend of 3 and 4 September 2016 for the demolition and clearance of the northern bridge element.<ref>{{cite news|url=https://www.bbc.co.uk/news/uk-england-kent-37271071|title=M20 closure to remove collapsed bridge ends 'ahead of schedule'|work=BBC News|date=4 September 2016|access-date=4 September 2016}}</ref> A replacement pedestrian and cycle bridge was opened in March 2021 at a cost of around £1.5&nbsp;million.<ref>{{cite news|url=https://www.kentonline.co.uk/malling/news/replacement-bridge-over-m20-now-open-244474/|title=East Street footbridge over M20 at Addington now open to the public|date=25 March 2021|newspaper=[[Kent Online]]}}</ref>

The [[Highways Agency]] proposed a new M20 junction 10a and link road to the A2070 at Ashford in Kent, east of junction 10,<ref>{{cite web|url=http://www.highways.gov.uk/roads/projects/5703.aspx|publisher=Highways Agency|title=M20 Junction 10A Scheme Page}}</ref> to support the development of South Ashford which has been identified as a growth area in the South East. In May 2012, it was announced that the scheme would be postponed for the short-term future. Planning recommenced in 2016.<ref>{{cite web|url=http://www.highways.gov.uk/roads/road-projects/m20-junction-10a/|title=M20 Junction 10a – Road Projects|publisher=[[Highways Agency]]|access-date=18 December 2012}}</ref> Work started on building the scheme in January 2018, with works planned to complete in May 2020.<ref>{{cite web |title=Improvements and major road projects - M20 J10a |work=Highways England Improvements and major road projects |url=https://highwaysengland.co.uk/projects/m20-junction-10a/ |publisher=Highways England |access-date=13 September 2018}}</ref> The coast-facing sliproads at the existing junction 10 were closed to allow the final works on the London-facing sliproads at junction 10a and the new junction opened on 31 October 2019.<ref>{{Cite web|url=https://www.kentonline.co.uk/ashford/news/new-motorway-junction-opens-215258/|title=New motorway junction opens|date=31 October 2019|website=Kent Online|language=en|access-date=15 December 2019}}</ref>

==Operation Stack and Operation Brock==
{{main|Operation Stack}}
Since the opening of the Channel Tunnel, sections of the M20 have been used occasionally for the implementation of Operation Stack, should the ferries and/or Channel Tunnel stop running. This closes that part of the motorway and uses the area as a lorry park until the ferries and/or Channel Tunnel are fully running again.

[[Operation Brock]] was the replacement for Stack, to be used in the event of [[no-deal Brexit]].

In July 2020, the government announced that it had bought a site beside junction 10A to build the [[Sevington customs clearance facility and lorry park]].<ref>{{cite news|url= https://www.theguardian.com/politics/2020/jul/10/vast-brexit-customs-clearance-centre-to-be-built-in-kent |title= Vast Brexit customs clearance centre to be built in Kent |work= The Guardian|author = Lisa O'Carroll | date= 10 July 2020 | access-date = 8 August 2020}}</ref><ref>{{cite news |url= https://www.theguardian.com/politics/2020/jul/16/brexit-kent-customs-facility-will-be-also-be-used-as-lorry-park-minister-confirms |title= Kent customs facility will also be used as lorry park, minister confirms |work= The Guardian|author = Lisa O'Carroll | date= 16 July 2020 | access-date = 8 August 2020}}</ref>

==Junctions==
Data from [[driver location signs]] are used to provide distance in kilometres and carriageway identifier information.<ref>
[http://www.trafficengland.com/map.aspx Traffic England Live Traffic Condition Map] {{webarchive|url=https://web.archive.org/web/20120210221222/http://www.trafficengland.com/map.aspx |date=10 February 2012 }} ''Highways Agency'' – Locations extracted from Traffic Camera Popup identifier text 
</ref> Where a junction spans several hundred metres and start and end points are available, both are cited. 
{| style="margin-left:1em; margin-bottom:1em;" class="wikitable"
|-  style="background:#0080d0; text-align:center; color:white; "
| colspan="4" | M20 motorway
|-  style="background:#000; text-align:center; color:white;"
| mile (km)
| Westbound exits (B carriageway)
| Junction
| Eastbound exits (A carriageway)
|- style="text-align:center;"
|
| ''Road continues as A20''<br><br>London (SE), Lewisham [[A20 road (England)|A20]]
| rowspan="2" | J1
| [[Dartford Crossing]], [[Gatwick Airport|Gatwick]] {{rail-interchange|air}} [[M25 motorway|M25]] <br>[[West Kingsdown]] [[A20 road (England)|A20]]<br>[[Swanley]] [[List of B roads in Great Britain|B2173]]<br>''Non-motorway traffic''
|- style="text-align:center;"
| {{convert|28.7|km|mi|1|order=flip|abbr=values}}
| [[Dartford Crossing]] [[M25 motorway|M25]]<br>[[Central London]] ([[A2 road (England)|A2]])<br>Swanley B2173
| ''Start of motorway''
|- style="text-align:center;"
|{{convert|42.2|km|mi|1|order=flip|abbr=values}} <br> {{convert|42.4|km|mi|1|order=flip|abbr=values}}
|{{no2}} No access
| J2
| [[Paddock Wood]] [[A20 road (England)|A20]] (B2016)<br>[[Gravesend, Kent|Gravesend]], [[Tonbridge]] ([[A227 road|A227]])<br>[[Wrotham]]
|- style="text-align:center;"
|{{convert|45.3|km|mi|1|order=flip|abbr=values}} <br> {{convert|45.8|km|mi|1|order=flip|abbr=values}}
| [[M26 motorway|M26]]<br>([[M25 motorway|M25 (CW)]])<br>[[Heathrow Airport|Heathrow]] {{rail-interchange|air}}, [[Gatwick Airport|Gatwick]] {{rail-interchange|air}}<br>[[Sevenoaks]] ([[A25 road|A25]])
| J3
|{{no2}} No access
|- style="text-align:center;"
|{{convert|49.7|km|mi|1|order=flip|abbr=values}} <br> {{convert|50.3|km|mi|1|order=flip|abbr=values}}
| [[West Malling]], [[Rochester, Kent|Rochester]], Tonbridge [[A228 road|A228]]
| J4
| West Malling, Rochester, New Hythe A228
|- style="text-align:center;"
|{{convert|54.1|km|mi|1|order=flip|abbr=values}} <br> {{convert|54.8|km|mi|1|order=flip|abbr=values}}
| Aylesford A20
| J5
| Maidstone, Aylesford A20
|- style="text-align:center;"
|{{convert|56.2|km|mi|1|order=flip|abbr=values}} <br> |{{convert|56.9|km|mi|1|order=flip|abbr=values}}
| Maidstone, [[Chatham, Kent|Chatham]] [[A229 road|A229]]
| J6
| Maidstone, Chatham A229
|- style="text-align:center;"
|{{convert|59.2|km|mi|1|order=flip|abbr=values}} <br> {{convert|59.8|km|mi|1|order=flip|abbr=values}}
| Maidstone, [[Sittingbourne]], [[Sheerness]] [[A249 road|A249]]
| J7
| Maidstone, Sheerness A249
|- style="text-align:center;"
|{{convert|64.7|km|mi|1|order=flip|abbr=values}} <br> {{convert|65.1|km|mi|1|order=flip|abbr=values}}
| Maidstone (East) A20
| J8
| Lenham A20
|- style="text-align:center;"
|{{convert|86.3|km|mi|1|order=flip|abbr=values}} <br> {{convert|87.0|km|mi|1|order=flip|abbr=values}}
| Ashford A20<br>[[Tenterden]], [[Canterbury]] [[A28 road|A28]]<br> [[Faversham]] [[A251 road|A251]]
| J9
| Ashford A20<br>Faversham A251
|- style="text-align:center;"
|{{convert|90.5|km|mi|1|order=flip|abbr=values}} <br> {{convert|91.0|km|mi|1|order=flip|abbr=values}}
|{{no2}} No access
| J10
| Ashford A292
|- style="text-align:center;"
|
|Ashford [[A roads in Zone 2 of the Great Britain numbering scheme#Triple-digit roads|A292]]<br>Hastings [[A2070 road (Great Britain)|A2070]]
| J10a
| Hastings A2070
|- style="text-align:center;"
|{{convert|101.5|km|mi|1|order=flip|abbr=values}} <br> {{convert|102.2|km|mi|1|order=flip|abbr=values}}
| Canterbury [[List of B roads in Great Britain|B2068]]<br>Hythe ([[A261 road|A261]])
| J11
| Canterbury B2068<br>Hythe (A261)
|- style="text-align:center;"
|{{convert|105.8|km|mi|1|order=flip|abbr=values}}
|{{no2}} No access
| J11a
| [[Channel Tunnel]] <br> (Local access to Lyminge)
|- style="text-align:center;"
|{{convert|107.5|km|mi|1|order=flip|abbr=values}} <br> {{convert|107.8|km|mi|1|order=flip|abbr=values}}
| Cheriton, Channel Tunnel A20
| J12
| Cheriton, Channel Tunnel A20
|- style="text-align:center;"
|{{convert|109.4|km|mi|1|order=flip|abbr=values}} <br> {{convert|109.6|km|mi|1|order=flip|abbr=values}}
| ''Start of motorway''
| rowspan="2"|J13
| Folkestone A20
|- style="text-align:center;"
|
| [[Folkestone]] A20
| ''Road continues as A20 to [[Dover]]'' 
|}

==See also==
*[[List of motorways in the United Kingdom]]
*[[Great Britain road numbering scheme]]
*[[:Category:M20 motorway service stations]]

==References==
{{reflist}}

==External links==
{{Attached KML|display=inline,title}}
*[https://web.archive.org/web/20061025190102/http://www.iht.org/motorway/m20londfolk.htm The Motorway Archive – M20]

{{UK motorways|state=collapsed}}
{{Motorways and Trunk Roads in England|state=collapsed}}

{{DEFAULTSORT:M20 Motorway}}
[[Category:Motorways in England|2-0020]]
[[Category:Roads in Kent|2-0020]]
[[Category:Transport in the Borough of Ashford]]
[[Category:Transport in Folkestone and Hythe]]