M74

M74 Motorway
The M74 runs between Glasgow and the English Border at Gretna near Carlisle.
Strictly speaking it is two distinct roads; the northern section (Glasgow to Abington) being the M74 and the southern section the A74(M). As I understand it this is because the southern section is upgraded dual carriageway and the northern section is 'new build'.
At present the A74(M) ends six miles short of the M6 motorway in northern England. The two motorways are joined by the A74. Which runs through the Cumberland Gap. Work is well underway to upgrade this section of road to motorway standard, and should be completed by late 2008.

There is some debate about whether the road will be renamed on completion of this work. It seems logical that it will become the M6, thus providing one simple route designation from Glasgow to the M1 at Rugby in the English midlands. The Scottish Government may well have other ideas, however.
Comments, corrections, suggestions