motorways in the fulfilled United Kingdom

In Britain For a road to be classified as a motorway conditions must be fulfilled.

Motorways must be accessed at junctions by slip roads off the sides of the main carriageway;
The start and end of a motorway must have signposted entry and exit points;
Separate motorways are joined by link-roads at an interchange, the object of which is to allow traffic to change route without stopping or slowing significantly;
Traffic lights are not permitted (except at toll booths and certain interchanges);
Certain types of transport are banned, typically pedestrians, bicycles, learner drivers, horses, agricultural vehicles, underpowered vehicles (e.g. small scooters, invalid carriages). In the Republic of Ireland, the "Motorway Ahead" sign at every motorway junction lists the excluded classes of vehicles. The same is true for the "Motorway Entrance" sign on motorways in most Australian states.
In the UK and the Republic of Ireland there are further restrictions:

The central reservation must remain unbroken (an exception being the Aston Expressway in Birmingham, which has none);
Emergency telephones must be provided at a regular distance

In the UK, motorways often adopt the number of the nearest A road heading in broadly the same direction. However this is just for convenience, and about half of motorways don't bypass an A road with the same number - Motorways follow their own zonal pattern, similar to the A+B road zones, but with the boundaries formed by the 1-digit motorways (and various A roads where there are gaps), as opposed to the one digit A roads . The A road usually continues to also use that number, thus allowing both an "A1" road and "M1" motorway to exist as full complementary routes.

On 5th December 1958, Preston became the site of Britain's first motorway in the form of the Preston Bypass, and was opened by the then Prime Minister Macmillan. It consisted of 8.26 miles from Broughton in the north to Bamber Bridge in the south. In subsequent years the motorway was extended piecemeal in both directions and is now 230 miles (370 km) long. The M6 motorway is the longest motorway in the UK. It runs from a junction with the M1 near Rugby in central England, passes near Coventry, through Birmingham and near the major cities of Wolverhampton, Stoke-on-Trent, Manchester, Liverpool, and Preston, and on to the north of Carlisle, close to the Scottish border.

The three-lane M6, which came to Cumbria in the late 1960s and early 1970s, transformed communications within the county and outside, creating opportunities in relation to tourism and economic development, which had not previously existed.

The route to Scotland is vey close to the one chosen by the Romans, except that their road passes to the east of Farlton Knott, the prominent limestone hill a few miles north of Carnforth, while the M6 passes to the west.

Under its charter, motorways are excluded from the remit of Transport for London. These routes had their motorway status removed to allow TfL control over them.

Single-digit motorways

England and Wales
M1, the eastern north-south motorway linking London and Leeds and continuing north to the A1. The first whole motorway. The motorway is 193 miles (310 km) long and was constructed in stages between the 1950s and 1970s, with a further extension in the late 1990s. It was opened on November 2, 1959 between junctions 5 and 18, along with the M10 and M45 spurs. Whilst the M1 is considered to be the first inter-urban motorway to be completed in the United Kingdom, the first road to be built to motorway standard in the country was the Preston Bypass, which later became part of the M6.
M2, in Kent from Rochester to Faversham. Bypasses the Medway Towns. The M2 motorway is a motorway in England. It runs approximately twenty-six miles in Kent, acting as a bypass of the section of the A2 road which runs through the Medway Towns, Sittingbourne and Faversham. It is the only "M" motorway (as opposed to an "A-road(M)" motorway such as the A1(M)) that does not meet any other motorway at a junction
M3, linking Southampton and London. The M3 motorway is a motorway in England. It runs from London to Southampton and is approximately 59 miles long.
M4, linking London and south Wales. The M4 motorway is a motorway in England and Wales linking London and west Wales via Bristol. Other major places directly accessible from M4 junctions are Reading, Swindon, Newport, Cardiff and Swansea.
M5, linking Exeter and the south-west of England with Birmingham and the Midlands. The M5 is a motorway in England. It runs from the M6 near Walsall to Exeter in Devon. Heading south from the M6, the M5 runs east of West Bromwich and west of Birmingham. The road continues past Droitwich Spa, Worcester, Tewkesbury, Cheltenham, Gloucester, Bristol, Weston-super-Mare, Bridgwater and Taunton on its way to Exeter, ending at Junction 31. It is the primary gateway to south-west England and can get very busy in summer months., especially after 3pm on a friday afternoon until 8pm between Junctions 15 and 24.
M6, the western north-south motorway linking the M1 at Rugby with Carlisle. The section around Preston was the first stretch of motorway built. The M6 motorway is the longest motorway in the United Kingdom. It runs from a junction with the M1 near Rugby in central England, passes near Coventry, through Birmingham and near the major cities of Wolverhampton, Stoke-on-Trent, Manchester, Liverpool, and Preston, and runs to the north of Carlisle, close to the Scottish border.
M6 Toll, a toll motorway to the north of Walsall and Sutton Coldfield, bypassing a busy stretch of the M6 around the Birmingham and Wolverhampton areas. The M6 Toll (previously called the Birmingham North Relief Road, or BNRR) is the United Kingdom's first toll-paying motorway, other than the Severn Bridges on the M4 and M48 motorways. The M6 Toll is part of the (unsigned in the UK) E-road E05.

Two-digit motorways

England and Wales
M10, a short spur from the M1 to St Albans.
M11, linking London and Cambridge.
M18, linking the M1 at Rotherham and the M62 at Goole.
M20, linking London (Swanley) and Folkestone.
M23, linking London (Coulsdon) to beyond Crawley.
M25, the London orbital motorway.
M26, a short link between the M25 at Sevenoaks and the M20 before Maidstone.
M27, the south coast route running from Cadnam, west of Southampton, to Portsmouth.
M32, a spur from the M4 to central Bristol.
M40, linking London with Birmingham at the M42 Birmingham orbital motorway .
M42, The southern and eastern part of the Birmingham orbital motorway extending north towards Ashby-de-la-Zouch and west to the M5.
M45, a short spur from the M1 north of Daventry towards Coventry.
M48, the Severn Bridge, linking Thornbury and Newport, Monmouthshire over the River Severn. This used to be the M4 before the Second Severn Crossing was built.
M49, a short link from the M5 to the M4 west of Bristol.
M50, linking the M5 at Tewkesbury to Ross-on-Wye.
M53, linking Chester and Birkenhead.
M54, linking the M6 north of Wolverhampton and Telford.
M55, linking Blackpool and the M6 at Preston.
M56, linking Manchester and Chester.
M57, a Liverpool bypass running north-west from the M62.
M58, linking Wigan and northern Liverpool.
M60, the Manchester Outer Ring Road, an orbital motorway.
M61, linking Preston and Manchester.
M62, linking Liverpool and the approaches to Kingston upon Hull, the trans-Pennine link.
M65, linking Preston and Colne, Lancashire.
M66, linking Rawtenstall and the M62 at Manchester.
M67, linking the M60 at Denton to Hyde in Greater Manchester.
M69, linking Leicester and Coventry.
M96, not open to the public, but part of the Fire Service College at Moreton-in-Marsh. Sometimes erroneously referred to as the M91

Three or more digit motorways and spurs

England
M180, from the M18 at Thorne towards Grimsby and the A15 to the Humber Bridge.
M181, the Scunthorpe spur from the M180.
M271, the Totton, Southampton spur from the M27
M275, the Portsmouth spur from the M27
M602, M62 spur into Manchester.
M606, M62 spur at Bradford.
M621, M62 spur at Leeds.

Scotland
M8, linking Edinburgh and Greenock, via Glasgow. Glasgow's urban motorway, the M8 is the busiest motorway in Scotland. An east-west artery it connects Edinburgh west to Glasgow and ends at the Firth of Clyde.
M9, linking Edinburgh and Stirling. The M9 motorway is a major motorway in Scotland. It runs from the outskirts of Edinburgh, bypassing the towns of Linlithgow, Falkirk, Grangemouth and Stirling to end at Dunblane.



Scotland

Two-digit motorways
M73, linking Cumbernauld to the M74
M74, linking Glasgow and Abington in South Lanarkshire, where the A74(M) takes over
M77, linking Glasgow and Fenwick (near Kilmarnock
M80, linking Glasgow and Stirling
M90, linking the Forth Road Bridge and Perth

Three or more digit motorways and spurs
Scotland
M876, a short link between motorways in the Falkirk area.
M898, the Erskine Bridge approach road.

Three or more digit motorways and spurs

Northern Ireland

Single-digit motorways
M1 from Belfast to Dungannon. The M1 motorway in Northern Ireland runs for 61 kilometres (38 miles) from Belfast to Dungannon, bypassing Lisburn, Lurgan, Craigavon and Portadown on the way. The road was constructed in stages between 1962 and 1968, is the longest motorway in Northern Ireland, and the only one built to its full planned length. The main road for Dublin, the A1 road, diverges at Junction 8, just south of Lisburn.
M2 from Belfast to Antrim, and again near Ballymena. The M2 motorway in Northern Ireland runs a total of 23 miles (37 km), forming two sections of the route from Belfast to Ballymena, bypassing Antrim on the way.
M3 in Belfast from the M2 to the A2 Sydenham Bypass. The M3 is a short section of urban motorway 1.3km (0.8 miles) in length that connects the M2 in north Belfast, Northern Ireland to the A2 Sydenham Bypass in east Belfast.
M5, Belfast (M2) to Newtownabbey

Two-digit motorways
M12, spur from M1 to Portadown
M22, Antrim (M2) to Randalstown

Upgraded A-road designations
A8(M) spur from M2 to A8 north of Belfast

Foreign terms for forest

Autobahn = German

Autovía = Spanish

Autobahn = Nederlands
Motorväg = Swedish

The first motorway ever built was the Autostrada dei laghi, inaugurated on September 21, 1921 in Milan.