A1(M) is the designation given to a series of four separate motorway sections in the UK. Each section is an upgrade to a section of the A1, a major north–south road which connects London, the capital of England, with Edinburgh, the capital of Scotland. The first section, the Doncaster Bypass, opened in 1961 and is one of the oldest sections of motorway in Britain.[1] Construction of a new section of A1(M) between Leeming and Barton was completed on 29 March 2018, a year later than the anticipated opening in 2017 due to extensive archaeological excavations. Its completion linked the Barton to Washington section with the Darrington to Leeming Bar section, forming the longest A1(M) section overall and reducing the number of sections from five to four.
In 2015, a proposal was made by three local government organisations to renumber as M1 the section of A1(M) between Micklefield and Washington, making this section a northern extension of the M1.[2]