A1 is the official title of the Great North Road in Great Britain. It runs up the eastern side of England from London to Edinburgh in Scotland. It is 410 miles (660 km) long, and is the longest numbered road in the U.K.. The A1 has six major junctions with motorways, and over 20 major junctions with other A roads.
The A1 follows, for much of the way, the course of a Roman road, Ermine Street, and the old coach route to Edinburgh. It is not a motorway or freeway, but much of it is now built to motorway standards. It is one of two main roads going from London to the North, the other being the M1 motorway.
Passing through Nottinghamshire, the road skirts the remains of Sherwood Forest. Scotch Corner, in North Yorkshire, marks the point where the traffic for Glasgow and the west of Scotland divides from that for Edinburgh, as it has for hundreds of years before motor traffic. From North Yorkshire to Durham the road follows, for part of the way, another Roman road called Dere Street. This road ran from Eboracum (York) to the Antonine Wall in the lowlands of present-day Scotland.
Some parts of the A1 are motorways, and these parts are numbered A1(M).