The list of motorways in the United Kingdom is a complete list of motorways in the United Kingdom. Note that whilst one numbering scheme is used for Great Britain, roads in Northern Ireland are allocated their own numbers on an ad hoc basis.
Roads which used to be motorways but have been downgraded:
The largest motorway project currently under construction in the UK is the £500m M8 Baillieston to Newhouse completion project, which includes 6 miles of new motorway on the M8 as well as junction upgrades and widenings to the M73 and M74. Work started in Spring 2014 with completion estimated for Spring 2017.
The £380m A1(M) Leeming - Barton upgrade also commenced construction in Spring 2014 with completion scheduled for Summer 2017.
The Queensferry Crossing and its approach roads are also being constructed as a motorway and will extend the M90 to the M9 at junction 1a re-numbering the M9 spur when finished in 2016.
The only other new motorway constructions currently being planned in the UK is a motorway running south of the city of Newport, south Wales. This motorway remains to be properly named, only being described as the M4 relief road.
There have been many plans for motorways in the UK that have not been built. Below is a list of plans that were not built (not exhaustive):
M12 in 3 forms:From the London end of the M11 to Brentwood;
From the London end of the M11 to Maplin Sands Airport (also not built);
From the M25 (in the vicinity of the M11) to Chelmsford.
M13, from East London to Maplin Sands airport passing south of Southend.
M17 Castle Donington bypass, a short spur off the M1;
M31, a bypass of the busiest section of the M25, cutting the corner for traffic from the West.
M59, M58 junction 2 to south of Preston.
M64, between the M6 south of Stoke-on-Trent and the M1 near Derby. Mostly built as the A50.
M601, which would have entered Manchester from the M62 (now the M60) in the Irwell Valley at Clifton near Pendlebury.
M650, Airedale Motorway from near Silsden to Shipley.
A6(M) (or M66 extension), which would have formed an eastern bypass for Stockport. As of March 2006, this is still under the planning stage as part of the SEMMMS (south east Manchester multi modal study) project (though not as motorway).
A556(M), which would have cut the corner between the M6 and M56 near Warrington.
Chippenham Spur, off the M4
Strensham – Solihull motorway, a link between the M50 and M42 or M69
Most of the M67 – from Hattersley to the M1 via the Hope Valley in the Peak District national park and Sheffield. Various routes have been proposed but have yet to come to fruition due to controversy and/or expense. Sheffield Hallam MP and former Deputy Prime Minister, Nick Clegg has also been signalling his support for the scheme. The latest proposal to extend the M67 is to tunnel under the Peak District from Hattersley to Stannington (an outer-suburb of Sheffield) and to link that tunnel to a new underground motorway providing links to the M1.
Many cities had urban motorway plans, most of which were not built. London, Newcastle, Liverpool, Manchester/SELNEC and Glasgow all had extensive plans.
The following motorways were planned, but never built.
M11, from the M1 going through Lisburn and then crossing the M1 again and ending at Newry
M23, from the M2 to Derry
There were also urban motorway plans for Belfast
