The A1 is the latest in a series of routes north from London to York and beyond, and was formed in 1921 by the Ministry of Transport as part of the Great Britain road numbering scheme.
The earliest documented northern routes out of London are the roads created by the Romans during the period 43 to 410 AD, which consisted of a variety of "Iters" on the Antonine Itinerary, a combination of which were used by the Anglo-Saxons as the route from London to York, and which became known as Ermine Street.
Ermine Street later became known as the Old North Road, and is used within London by the current A10.
By the 12th century, because of flooding and damage by traffic on Ermine Street, an alternative route out of London was found through Islington and Muswell Hill, and this was the origin of the Great North Road that would become the A1.
Until the 14th century the route went up what is now Hornsey Road – the A103 road, but when that became impassable a new route along Holloway Road via Highgate was created in the 14th century.
The section through Highgate was bypassed in the early 19th century by the creation of a new road, Archway Road, and around the same time a turnpike road, New North Road and Canonbury Road (the A1200 road), was constructed linking the start of the Old North Road around Shoreditch with the Great North Road at Highbury Corner.

The route of the A1 in London originally started at Aldersgate Bars, which marked the boundary of the City of London, and followed the Great North Road mail coach route through Barnet; the route was re-designated in 1954 to follow the East Finchley and Barnet by-passes built in the 1920s and 1930s, so within London the coaching route is now mainly only followed when passing through the borough of Islington.
During the early 1970s plans to widen the A1 along the Archway Road section were abandoned after considerable opposition and four public inquiries during which road protesters disrupted proceedings.
The scheme was finally dropped in 1990.
The A1 is the latest in a series of routes north from London to York and beyond, and was formed in 1921 by the Ministry of Transport as part of the Great Britain road numbering scheme. The earliest documented northern routes out of London are the roads created by the Romans during the period 43 to 410 AD, which consisted of a variety of "Iters" on the Antonine Itinerary, a combination of which were used by the Anglo-Saxons as the route from London to York, and which became known as Ermine Street. Ermine Street later became known as the Old North Road, and is used within London by the current A10. By the 12th century, because of flooding and damage by traffic on Ermine Street, an alternative route out of London was found through Islington and Muswell Hill, and this was the origin of the Great North Road that would become the A1. Until the 14th century the route went up what is now Hornsey Road – the A103 road, but when that became impassable a new route along Holloway Road via Highgate was created in the 14th century. The section through Highgate was bypassed in the early 19th century by the creation of a new road, Archway Road, and around the same time a turnpike road, New North Road and Canonbury Road (the A1200 road), was constructed linking the start of the Old North Road around Shoreditch with the Great North Road at Highbury Corner.
The route of the A1 in London originally started at Aldersgate Bars, which marked the boundary of the City of London, and followed the Great North Road mail coach route through Barnet; the route was re-designated in 1954 to follow the East Finchley and Barnet by-passes built in the 1920s and 1930s, so within London the coaching route is now mainly only followed when passing through the borough of Islington. During the early 1970s plans to widen the A1 along the Archway Road section were abandoned after considerable opposition and four public inquiries during which road protesters disrupted proceedings. The scheme was finally dropped in 1990.
A1 in London