Some sections of the A1 have been upgraded to motorway standard. These are known as the A1(M). These include a long stretch coming north from London from the M25 to just north of Baldock; the new Peterborough section from the Alconbury junction near Huntingdon; a section bypassing Doncaster and intersecting the United Kingdom); a short section where the new extended M1 joins the road between Leeds and York and a relatively new section through North Yorkshire east of Ripon, and another long stretch south of Newcastle upon Tyne.
The A1, at 409 miles (658 km) long, is the longest numbered British road.
However, where there arises a need to distinguish between the modern road, on its bypasses and some former part of the road, where it passed through the various towns, the name "A1" is sometimes reserved for the modern road, while "the Great North Road" refers to its original course.
Improvements to the road north of Newcastle upon Tyne are also being undertaken where the road consists mostly of single carriageway sections as opposed to a combination of dual carriageway and motorway to the south.