View source for M3 motorway (Great Britain)

{{Short description|Major motorway in England}}
{{Use British English|date=May 2014}}
{{Use dmy dates|date=August 2020}}
{{infobox road
|country=GBR
|type=M
|route=3
|photo= Twyford down cutting 03.jpg
|photo_notes= Looking south at [[Twyford Down]], 2006
|maint= [[National Highways]]
|length_mi=59
| map = {{switcher
  | {{maplink-road|from=M3 motorway (Great Britain).map}}M3 highlighted in blue{{hr}}
  | Show interactive map
  | [[File:M3 motorway (Great Britain) map.svg|frameless|x323px]]<br />Shown with UK motorway network{{hr}}
   | Show UK motorways map
   }}
|map_custom=yes
|map_notes=
|direction_a= Northeast
|terminus_a=          {{plainlist|
* [[Sunbury-on-Thames]]
* {{coord|51.4166|-0.4240|type:landmark_region:GB|display=inline|name=M3 motorway (northeastern end)}}
  }}
|counties= [[Surrey]], [[Hampshire]]
|destinations= [[London]]<br>[[Bracknell]]<br>[[Aldershot]]<br>[[Basingstoke]]<br>[[Winchester]]<br>[[Southampton]]<br>[[Reading, Berkshire|Reading]]<br>[[Newbury, Berkshire|Newbury]]
|direction_b= Southwest
|terminus_b=            {{plainlist|
* [[Chilworth, Hampshire|Chilworth]]
* {{coord|50.9545|-1.4081|type:landmark_region:GB|display=inline|name=M3 motorway (southwestern end)}}
  }}
|established=   1971
|history= {{plainlist|
* Opened: 1971
* Completed: 1995
  }}
|junction=      {{plainlist|
* [[File:Junction 2.svg|1000x20px]] [[File:UK-Motorway-M25.svg|1000x20px]]
* J2 → [[M25 motorway]]
* [[File:Junction 14.svg|1000x20px]] [[File:UK-Motorway-M27.svg|1000x20px]]
* J14 → [[M27 motorway]]
  }}
|e-road={{Jct|country=EUR|E|05}}
|previous_type = M
|next_type     = M
|previous_route = 2
|next_route    = 4
|previous_dab  = Great Britain
}}

The '''M3''' is a [[controlled-access highway|motorway]] in England, from [[Sunbury-on-Thames]], Surrey, to [[Eastleigh]], Hampshire; a distance of approximately {{convert|59|mi|km|0}}. The route includes the [[Aldershot Urban Area]], [[Basingstoke]], [[Winchester]], and [[Southampton]].

It was constructed as a dual three-lane motorway except for its two-lane section between junction 8 ([[A303 road|A303]]) and junction 9. The motorway was opened in phases, ranging from [[Lightwater]]/[[Bagshot]] to [[Popham, Hampshire|Popham]] in 1971 to Winchester to [[Otterbourne]] Hill in 1995. The latter stages attracted opposition from environmental campaigns across Britain due to its large [[cutting (transportation)|cutting]] through wooded [[Twyford Down]]; numerous [[Road protest in the United Kingdom#1979.E2.80.931997|road protests]] were held which delayed its opening. Similar protests were avoided on the near-parallel [[A3 road|A3]] by the construction of the [[Hindhead Tunnel]]. Since completion, the motorway has been an artery to the west and midsections of the [[Southern England|South Coast]] and [[Isle of Wight]] including for tourism. The major settlements nearest to the motorway are served by a railway also used for [[London commuter belt|commuting]] but are relatively [[dispersed settlement|dispersed]]. Traffic on the M3 sees delays and congestion on its busiest sections near commuting hotspots and during holiday periods. From [[Chertsey]] to [[Fleet, Hampshire|Fleet]] the road was in 2017 converted to a [[Managed motorways in the United Kingdom|Smart Motorway]], turning the hard shoulder into a permanent fourth lane with emergency refuge lay-bys.<ref>{{cite web|url=https://www.gov.uk/government/news/m3-gets-first-orange-smart-motorway-emergency-area|title=M3 gets first 'orange' smart motorway emergency area}}</ref>

==History==
[[File:M3 - East Stratton.jpg|thumb|M3 motorway at [[East Stratton]]]]
[[File:M3 - Southampton.jpg|thumb|Southern end of the M3 meeting the [[A33 road|A33]] at Southampton]]
[[File:Fleet - geograph.org.uk - 3815.jpg|thumb|M3 motorway at [[Fleet, Hampshire|Fleet]]]]
[[File:Twyford down.jpg|thumb|M3 under construction at [[Twyford Down]]]]
{{see also|Twyford Down}}
The motorway was originally approved as the "London to Basingstoke Motorway" with delays over funding for an extension to Southampton<ref>{{cite web|url=https://api.parliament.uk/historic-hansard/lords/1967/jun/21/the-m3-motorway|title=The M.3 Motorway|work=[[Hansard|Parliamentary Debates (Hansard)]]|year=1967}}</ref> the road was built to relieve two single carriageway trunk roads that were congested.{{#tag:ref|*The [[A30 road|A30]] eastern stretch to the [[A303 road]]<br>*The Winchester to Southampton traditional road, the [[A33 road|A33]]|group= n}}<ref name=lordshepherd/>

In 1967, sections of the A33 from Popham, Hampshire, to a northeastern point of the Winchester Bypass were widened to dual carriageways; this only partially alleviated growing congestion, especially in [[Winchester]], which led to the southern phase gaining approval.{{#tag:ref|Of the [[A34 road (England)|A34 trunk road]] from [[Bicester]] on the M40 to [[Southampton]]|group= n}}<ref name=lordshepherd>{{cite web|url=https://api.parliament.uk/historic-hansard/lords/1967/jun/21/the-m3-motorway|title=The M.3 Motorway|work=[[Hansard|Parliamentary Debates (Hansard)]]|year=1967}} Oral Questions in the [[House of Lords]] 21 June 1967 vol 283 cc1385-7</ref>

===Eastern section===
The eastern section, from [[Sunbury-on-Thames]] in [[Surrey]] to Popham near [[Basingstoke]] opened in sections: first the [[Hampshire]] section in 1971, and then the Surrey section in 1974.<ref name=DfT6363>{{cite web|url=http://www.highways.gov.uk/roads/projects/6363.aspx|title=M3 London to Southampton Route Management Strategy|publisher=Department for Transport|url-status=dead|archive-url=https://web.archive.org/web/20070930201532/http://www.highways.gov.uk/roads/projects/6363.aspx|archive-date=30 September 2007}}</ref> The cost for this first phase was £46m.<ref>{{cite web|url=https://api.parliament.uk/historic-hansard/written-answers/1988/jan/11/m3-sunbury-popham|title=M3 (Sunbury-Popham)|work=[[Hansard|Parliamentary Debates (Hansard)]]|year=1988}}</ref> The completed road acts were as a continuation of the [[A316 road|A316 Country Way]], an express three-lane road from Apex Corner, [[Hanworth]], in [[Greater London]] to Sunbury-on-Thames.

The section is one of five routes into the southern half of London which reach Inner London with at least a dual-carriageway - or dual-direction - road, the others being the [[A3 road|A3]], the A30/A4, the [[A20 road (Great Britain)|A20]] and [[A2 road (Great Britain)|A2]]. However approximately one mile before reaching Inner London it combines with the routes of the A30 and M4 approaches.

===Southern section===
A first public inquiry for the "M3 London to Basingstoke Motorway: Popham to [[Compton and Shawford|Compton]] extension" centred on the section passing Winchester, and was held in 1971, after which the ministry was instructed to reconsider and reconsult on the proposals.<ref>{{cite web|url=http://www.nationalarchives.gov.uk/catalogue/displaycataloguedetails.asp?CATID=8280346&CATLN=6&accessmethod=5|title=M3 London to Basingstoke Motorway: Popham to Compton public inquiry|publisher=National Archives}}</ref><ref name=iht1>{{cite web|url=http://www.iht.org/motorway/m3londsouth.htm|title=M3. London to Southampton|publisher=The Motorway Archive|url-status=dead|archive-url=https://web.archive.org/web/20060905175247/http://www.iht.org/motorway/m3londsouth.htm|archive-date=5 September 2006}}</ref> A second public inquiry was held in 1976–77.<ref>{{cite web|url=https://api.parliament.uk/historic-hansard/commons/1976/jul/26/m3-motorway-inquiry|title=M3 MOTORWAY INQUIRY|work=[[Hansard|Parliamentary Debates (Hansard)]]|author=Morgan Morgan-Giles|date=26 July 1976|access-date=11 March 2013|author-link=Morgan Morgan-Giles}}</ref><ref>{{cite web|url=http://www.nationalarchives.gov.uk/catalogue/displaycataloguedetails.asp?CATID=8530136&CATLN=6&accessmethod=5|title=M3 London to Basingstoke motorway: Popham to Compton; public inquiry 1976|publisher=National Archives}}</ref> The earlier decision to route the motorway through or alongside the water meadows between [[St. Catherine's Hill, Hampshire|St Catherine's Hill]] and the compact [[cathedral city]] was reopened, and during the year-long inquiry the [[John Thorn (headmaster)|headmaster]] of [[Winchester College]] was forcibly ejected along with others for causing a disturbance.<ref name=iht1/>

The scope of the M3 extension was reduced to defer the difficult decision about the section around Winchester and it was built in two sections (from 'Popham to Bridget's Farm' and from 'Bridget's Farm to Bar End') in 1985.<ref name=DfT6363/> When this opened, the temporary junction to the A33 parallel route was removed.

The section of the M3 from near Junction 12 ([[Eastleigh]] and [[Chandler's Ford]]) to the last, Junction 14 for the [[M27 motorway|M27]] replaced part of the A33, which was upgraded to motorway standard and opened in 1991.<ref name=iht1/>

In 2008, the busiest section of the motorway, at Chandler's Ford, carried a daily average of around 130,000 vehicles.<ref>{{cite web |title=Annual Average Daily Traffic Flows|publisher=Department for Transport|url=http://www.dft.gov.uk/matrix/Default.aspx |access-date=28 September 2009}}</ref>

The southern section starts as a continuation of a single-lane avenue, Bassett Avenue and The Avenue in the [[City of Southampton]] as the M27 provides alternative routes from other parts of the city, particularly its waterfront and downtown peak-hour accessway, the [[M271 motorway]] and Mountbatten Way providing dual to three lane highways starting at the northwest of the city.

===Abandoned/suspended proposals===
A service station was envisaged at Basingstoke upon the motorway's completion but not built – superseded by one just north of [[Fleet, Hampshire|Fleet]] and another north of Winchester.{{cn|date=August 2024}}
Plans for a Basingstoke Services were again published in November 2017<ref>{{cite web|url=https://www.basingstokegazette.co.uk/news/15654729.plan-for-new-m3-service-station-including-100-room-hotel-at-basingstoke/ |title=New Basingstoke Services|date=12 November 2017 }}</ref>

===Additions===
An additional junction, numbered 4A, was opened in April 1992 for Fleet.<ref name="harms">{{cite web|url=http://www.highways.gov.uk/roads/projects/6363.aspx|title=Highways Agency: M3 London to Southampton Route Management Strategy|publisher=Highways Agency|url-status=dead|archive-url=https://web.archive.org/web/20070930201532/http://www.highways.gov.uk/roads/projects/6363.aspx|archive-date=30 September 2007}}</ref>

==Detailed route==
The M3 starts at Sunbury-on-Thames in Surrey on the edge of South West London as the continuation of the [[A316 road|A316]] which has three lanes each way from Hanworth in the [[London Borough of Hounslow]], and two from [[Chiswick]]. The motorway {{convert|2|mi}} after its start turns more [[boxing the compass|west-southwest]],<ref>[http://gridreferencefinder.com/ Grid Reference Finder] distance tools</ref> crosses the [[River Thames]] on the [[M3 Chertsey Bridge]] to the north of [[Chertsey]] and then has its second junction, at the [[M25 motorway]], before continuing through the gorse, bogs and heather of the [[Surrey Heath]].  Its third junction is for [[Camberley]], Bagshot, [[Bracknell]], [[Ascot, Berkshire|Ascot]] and [[Worplesdon]].  From Junction 4 it bisects the northern [[Blackwater Valley conurbation]]{{#tag:ref|Main settlements: [[Farnborough, Hampshire|Farnborough]], [[Aldershot]], [[Camberley]], [[Frimley]], [[Farnham, Surrey|Farnham]] and [[Sandhurst, Berkshire|Sandhurst]]|group= n}} then has its latest junction for Fleet and nearby early 21st century expanded/new villages{{#tag:ref|Examples include [[Elvetham Heath]]|group= n}}, it crosses the [[South West Main Line]], before skirting [[Old Basing]] and Basingstoke to its north{{#tag:ref|Here the M3 passes close to the [[Basingstoke Canal]]|group= n}}. Turning south west again, it passes Popham and, just before reaching Junction 8, where one lane becomes the A303 which leads to [[Exeter]] and [[South West England]]. From here the motorway continues as a dual two lane road through open [[countryside]] and [[Micheldever Wood]] until it reaches the north of [[Winchester, England|Winchester]].

Taking over the  "Winchester Bypass" the M3 resumes to three lanes each way at Junction 9, continues directly south and then takes a small curve around the east of the city running through a deep cutting in [[Twyford Down]] and then proceeding south west again, crossing the South West Main Line a second time alongside the [[River Itchen, Hampshire|River Itchen]] and through the Eastleigh [[urban area|urban]]-suburban area before crossing the [[Eastleigh to Romsey Line|Eastleigh to Romsey railway line]] and ending at the Chilworth Roundabout on the edge of Southampton.

===Road features===
*The '''Spitfire Bridge''' carries the B3404 Alresford Road from Winchester over the M3 motorway and the parallel A272 (J9-J10 spur, known as the "Spitfire Link"). It replaced a concrete [[parabolic arch]] bridge under which a [[Curtiss P-40 Warhawk|Curtiss P-40]] had been flown by George Rogers in October 1941. It was generally assumed locally that the aircraft had been a Spitfire, hence the name.<ref>{{Cite journal
|date = 31 October 2003
|journal = Southern Daily Echo
|title = Myth of pilot's bridge stunt 
|url =https://www.dailyecho.co.uk/news/5584779.myth-of-pilots-bridge-stunt/}}
</ref>

*A private exit of the northern roundabout connected to Junction 4a provides access to the former<ref>{{cite web|url=http://www.dbre.co.uk/News-former-sun-microsystems-hq-sold.html |title=DB Real Estate – Commercial Property Surveyors }}</ref> UK headquarters of [[Sun Microsystems]].<ref>{{cite web|url=http://www.hants.gov.uk/scrmxn/c25650.html |publisher=Hampshire County Council |work=Roads & Development Sub-committee |title=Off Site Highway Works and Contributions – Report of the County Surveyor |date=26 October 1998 |access-date=23 March 2008 |url-status=dead |archive-url=https://web.archive.org/web/20050218100428/http://www.hants.gov.uk/scrmxn/c25650.html |archive-date=18 February 2005 }}</ref> As of 2018, this is now a new housing estate, Helios Park<ref>{{Cite web | url=https://www.bellway.co.uk/new-homes/thames-valley/helios-park |title = New homes for sale in Hawley, Hampshire from Bellway Homes}}</ref>
*The section of the M3 between J2 and J4a has been converted into a [[smart motorway]], with full opening on 30 June 2017.<ref>{{cite web|url=http://roads.highways.gov.uk/projects/m3-junctions-2-4a-smart-motorway/ |publisher=Highways England |title=M3 junctions 2-4a: smart motorway |date=30 June 2017 |access-date=13 July 2017}}</ref>

==Incidents==
*In the early morning of 25 April 1999, the drum and bass DJ and record producer Valerie Olukemi "Kemi" Olusanya, known as [[Kemistry]], was killed on the M3 near Winchester by the steel body of a [[cat's eye (road)|cat's eye]], which had been dislodged by a van and flew through the windscreen of the following car in which she was a passenger. The object hit her in the face and killed her instantly. The [[coroner]] recorded a verdict of accidental death.<ref>{{cite web
| url         =http://www.dailyecho.co.uk/archive/1999/11/11/Hampshire+Archive/5632299.DJ_killed_by_flying_motorway_Cat_s_eye/
| work       = [[Southern Daily Echo]]
| access-date  =11 November 2009
| title        = DJ killed by flying motorway Cat's-eye
}}</ref><ref>{{cite web | url=https://mixmag.net/feature/dj-history-kemistry | title=DJ History: Kemistry }}</ref> A question was asked in the [[House of Lords]] about the safety of cat's eyes in light of the highly unusual incident, and the [[Highways Agency]] conducted an investigation into the "long-term integrity and performance" of various types of road stud.<ref>{{cite hansard | title=Written Answers {{ndash}} Cats-eyes: Safety Inspections|url=https://publications.parliament.uk/pa/ld199900/ldhansrd/vo991213/text/91213w05.htm#91213w05_sbhd3 | house=House of Lords | date=13 December 1999 | column=WA20 }}</ref>
*On 1 April 2000, a [[zebra crossing]] was illegally painted across the northbound carriageway of the M3 between Junctions 4 and 4a.<ref>{{cite news | url= https://news.bbc.co.uk/2/hi/uk_news/698144.stm | title= Police hunt motorway jokers | publisher= BBC News | date= 1 April 2000 | access-date=23 March 2008}}</ref>
*On 23 September 2017, two firebombs were thrown from a bridge onto the motorway between junctions 9 and 11 by 17-year-old Nicholas Elger (who suffered from a psychiactric illness) leading to an 11-hour closure costing the economy an estimated £40{{nbsp}}million.<ref>{{Cite news|date=2018-07-12|title=Winchester M3 arson: Teenager Nicholas Elger jailed|language=en-GB|work=BBC News|url=https://www.bbc.com/news/uk-england-hampshire-44812464|access-date=2021-12-19}}</ref> The attacker was identified after being linked to a bottle of [[Voss water]] used to transport the fuel. Elger told police he wished he had killed somebody and entered guilty pleas to two counts of arson recklessly endangering life.<ref>[http://www.hampshirechronicle.co.uk/news/16081726.Bottle_of___39_artisan__39__water_helped_link___40million_M3___39_fire_bomb__39__incident_to_Winchester_teen/ Bottle of 'artisan' water helped link £40million M3 'fire bomb' incident to Winchester teen Nicholas Elger]</ref>

==Junctions==
Data from [[driver location signs]] are used to provide distance and carriageway identification information.<ref>Area 3 Driver Location Signs (map) – Highway Authority, 2009{{Citation needed|date=March 2013}}</ref>

{| class="plainrowheaders wikitable"
|-
!scope=col|County
!scope=col|Location
!scope=col|{{tooltip|mi|Miles}}
!scope=col|{{tooltip|km|Kilometres}}
!scope=col|{{tooltip|Jct|Junction}}
!scope=col|Destinations (NE-bound)
!scope=col|Destinations (SW-bound)
!scope=col|Notes
|-
|rowspan=4|[[Surrey]]
|rowspan=2|[[Sunbury-on-Thames]]
|style="background:#eaecf0;text-align:right;"|15.0
|style="background:#eaecf0;text-align:right;"|24.2
|style="text-align:center;"|
|colspan=2|{{jct|country=GBR|A|316|city1=Central London|location2=[[Richmond-upon-Thames|Richmond]]}}
|Continuation beyond A308
|-
|style="background:#eaecf0;text-align:right;"|15.3
|style="background:#eaecf0;text-align:right;"|24.6
|style="text-align:center;"|1
|colspan=2|{{jct|country=GBR|A|308|city1=Staines|location2=[[Kingston upon Thames|Kingston]]|location3=[[Sunbury-on-Thames|Sunbury]]}}
|Northeastern terminus
|-
|[[Thorpe, Surrey|Thorpe]]–[[Chertsey]] boundary
|style="background:#eaecf0;text-align:right;"|21.3
|style="background:#eaecf0;text-align:right;"|34.2
|style="text-align:center;"|2
|{{jct|country=GBR|M|25|to2=to|M|23|noshield2=y|M|20|noshield3=y|extra=airport|location1=[[Gatwick Airport]]}} <br> {{jct|country=GBR|M|25|to2=to|M|4|noshield2=y|M|40|noshield3=y|M|1|noshield4=y|extra=airport|location1=[[Heathrow Airport]]|city2=Watford|city3=Staines}}
|{{jct|country=GBR|M|25|to2=to|M|23|noshield2=y|M|20|noshield3=y|A|320|noshield4=y|extra=airport|location1=[[Gatwick Airport]]|city2=Woking}} <br> {{jct|country=GBR|M|25|to2=to|M|4|noshield2=y|M|40|noshield3=y|M|1|noshield4=y|extra=airport|location1=[[Heathrow Airport]]|city2=Staines}}
|
|-
|[[Bagshot]]–[[Lightwater]] boundary
|style="background:#eaecf0;text-align:right;"|28.1
|style="background:#eaecf0;text-align:right;"|45.2
|style="text-align:center;"|3
|{{jct|country=GBR|A|322|city1=Woking|city2=Bracknell}}
|{{jct|country=GBR|A|322|city1=Bracknell|city2=Lightwater}}
|
|-
|[[Surrey]]–[[Hampshire]] boundary
|[[Camberley]]–[[Farnborough, Hampshire|Farnborough]] boundary
|style="background:#eaecf0;text-align:right;"|32.6
|style="background:#eaecf0;text-align:right;"|52.5
|style="text-align:center;"|4
|colspan=2|{{jct|country=GBR|A|331|city1=Guildford|city2=Farnham|location3=[[Farnborough, Hampshire|Farnborough]]}}
|
|-
|rowspan=15|[[Hampshire]]
|[[Farnborough, Hampshire|Farnborough]]–[[Blackwater and Hawley]] boundary
|style="background:#eaecf0;text-align:right;"|34.4
|style="background:#eaecf0;text-align:right;"|55.4
|style="text-align:center;"|4A
|colspan=2|{{jct|country=GBR|A|327|to2=to|A|3013|location1=[[Farnborough, Hampshire|Farnborough]]|location2=[[Fleet, Hampshire|Fleet]]}}
|
|-
|[[Hartley Wintney]]–[[Fleet, Hampshire|Fleet]]
|style="background:#eaecf0;text-align:right;"|
|style="background:#eaecf0;text-align:right;"|
|colspan=3 style="text-align:center;"|[[Fleet services]]
|
|-
|[[Hook, Hart|Hook]]–[[Odiham]] boundary
|style="background:#eaecf0;text-align:right;"|41.9
|style="background:#eaecf0;text-align:right;"|67.4
|style="text-align:center;"|5
|colspan=2|{{jct|country=GBR|A|287|to2=to|B|3349|location1=[[Hook, Hart|Hook]]}}
|
|-
|[[Old Basing]]–[[Basingstoke]] boundary
|style="background:#eaecf0;text-align:right;"|46.6
|style="background:#eaecf0;text-align:right;"|75.0
|style="text-align:center;"|6
|{{jct|country=GBR|A|339|to2=to|A|33|city1=Basingstoke|location2=[[Newbury, Berkshire|Newbury]]|location3=[[Alton, Hampshire|Alton]]|location4=[[Reading, Berkshire|Reading]]}}
|{{jct|country=GBR|A|339|city1=Basingstoke|location2=[[Alton, Hampshire|Alton]]}}
|
|-
|[[Dummer, Hampshire|Dummer]]
|style="background:#eaecf0;text-align:right;"|51.8
|style="background:#eaecf0;text-align:right;"|83.3
|style="text-align:center;"|7
|colspan=2|{{jct|country=GBR|A|30|city1=Basingstoke}}
|
|-
|[[Dummer, Hampshire|Dummer]]–[[Popham, Hampshire|Popham]] boundary
|style="background:#eaecf0;text-align:right;"|53.1
|style="background:#eaecf0;text-align:right;"|85.5
|style="text-align:center;"|8
|style="background:#ffdddd" title="Incomplete access"|No access
|{{jct|country=GBR|A|303|location1=The South West|location2=[[Andover, Hampshire|Andover]]|city3=Salisbury}}
|style="background:#ffdddd" title="Incomplete access"|Southwest-bound exit and northeast-bound entrance
|-
|[[Itchen Valley]]
|style="background:#eaecf0;text-align:right;"|59.9
|style="background:#eaecf0;text-align:right;"|96.4
|colspan=3 style="text-align:center;"|[[Winchester services]]
|
|-
|rowspan=2|[[Winchester]]
|style="background:#eaecf0;text-align:right;"|63.9
|style="background:#eaecf0;text-align:right;"|102.8
|style="text-align:center;"|9
|{{jct|country=GBR|A|34|location1=The Midlands|location2=[[Newbury, Berkshire|Newbury]]}}
|{{jct|country=GBR|A|272|city1=Winchester}}
|
|-
|style="background:#eaecf0;text-align:right;"|65.2
|style="background:#eaecf0;text-align:right;"|105.0
|style="text-align:center;"|10
|{{jct|country=GBR|A|31|to2=to|B|3330|location1=[[Alton, Hampshire|Alton]]|city2=Winchester}}
|style="background:#ffdddd" title="Incomplete access"|No access
|style="background:#ffdddd" title="Incomplete access"|Northeast-bound exit and southwest-bound entrance
|-
|[[Twyford, Hampshire|Twyford]]–[[Compton and Shawford]] boundary
|style="background:#eaecf0;text-align:right;"|67.2
|style="background:#eaecf0;text-align:right;"|108.1
|style="text-align:center;"|11
|colspan=2|{{jct|country=GBR|A|3090|city1=Winchester}}
|
|-
|rowspan=2|[[Eastleigh]]–[[Chandler's Ford]] boundary
|style="background:#eaecf0;text-align:right;"|70.0
|style="background:#eaecf0;text-align:right;"|112.6
|style="text-align:center;"|12
|{{jct|country=GBR|A|335|city1=Eastleigh}}
|{{jct|country=GBR|A|335|city1=Eastleigh|city2=Chandler's Ford}}
|
|-
|style="background:#eaecf0;text-align:right;"|
|style="background:#eaecf0;text-align:right;"|
|style="text-align:center;" rowspan=2|13
|{{jct|country=GBR|A|335|city1=Eastleigh|city2=Chandler's Ford}}
|{{jct|country=GBR|A|335|city1=Eastleigh}}
|
|-
|[[Eastleigh]]–[[Chandler's Ford]]–[[Chilworth, Hampshire|Chilworth]] boundary
|style="background:#eaecf0;text-align:right;"|
|style="background:#eaecf0;text-align:right;"|
|style="background:#ffdddd" title="Incomplete access"|No access
|{{jct|country=GBR|M|27|dir1=west|location1=[[Southampton Docks]]|city2=Bournemouth}}
|style="background:#ffdddd" title="Incomplete access"|Southwest-bound exit and northeast-bound entrance
|-
|[[Chilworth, Hampshire|Chilworth]]–[[Southampton]] boundary
|style="background:#eaecf0;text-align:right;"|
|style="background:#eaecf0;text-align:right;"|
|style="text-align:center;"|14
|style="background:#ffdddd" title="Incomplete access"|No access
|{{jct|country=GBR|M|27|dir1=east|extra=airport|location1=[[Southampton Airport]]|city2=Portsmouth}}
|style="background:#ffdddd" title="Incomplete access"|Southwest-bound exit and northeast-bound entrance
|-
|[[Chilworth, Hampshire|Chilworth]]
|style="background:#eaecf0;text-align:right;"|
|style="background:#eaecf0;text-align:right;"|
|style="text-align:center;"|
|colspan=2|{{jct|country=GBR|A|33|city1=Southampton}}
|Southwestern terminus
|-
|colspan=8|'''Notes'''
*Distances in kilometres and carriageway identifiers are obtained from [[driver location signs]]/location marker posts. Where a junction spans several hundred metres and the data is available, both the start and finish values for the junction are shown. 
|-
|colspan=8 style="background:#eaecf0;text-align:center;"| 1.000 mi = 1.609 km; 1.000 km = 0.621 mi <br> {{resize|{{legend|#ffdddd|[[Interchange (road)#Complete and incomplete interchanges|Incomplete access]]}}}}
|}

==See also==
* [[List of motorways in the United Kingdom]]

==Notes and references==
;Notes 
{{Reflist|group=n}}
;References
{{Reflist}}

==External links==
{{OSM relation|120904|M3 motorway|link=yes}}
{{GeoGroup}}
{{Attached KML|display=inline,title}}
{{commons category}}
*Chris's British Road Directory{{discuss|Chris's Road Directory|Discuss – April 2013}}
**[http://www.cbrd.co.uk/motorway/m3/ Motorway Database – M3]
**[https://web.archive.org/web/20120217085423/http://www.cbrd.co.uk/badjunctions/3-31.shtml 'Bad Junctions' – M3/A31 (Winchester)]
*[https://web.archive.org/web/20060905175247/http://www.iht.org/motorway/m3londsouth.htm The Motorway Archive – M3]

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

{{DEFAULTSORT:3-0003m}}
[[Category:Motorways in England]]
[[Category:Transport in Surrey]]
[[Category:Transport in Hampshire]]
[[Category:Roads in Surrey]]