A1/The Barnet By-Pass/A1(M)
The A1 was designated by the Ministry of Transport in 1921 and its original route ran through Potters Bar along the Great North Road.
The growing number of vehicles began to take it's toll on the Great North Road, its route through towns and villages meant that vehicles had to contend with
junctions and narrow lanes on the route north. The road named Barnet Bypass was the answer to the traffic problems in the area, a modern by pass road avoiding the towns
of Barnet and Potters Bar. The Barnet By pass cannot have been designed as a replacement for the A1 as it was first numbered the A5092, it was later numbered the
Finally in 1954 it replaced the Great North Road route and was designated as the A1, at this time the Great North Road route was re-designated the A1000.
The original Barnet By-Pass route ran along what is now Swanland Road which now runs from South Mimms Service Area to Welham Green. The Barnet By-Pass
met the A1081 Barnet to St Albans Road at a crossroads where the South Mimms M25/A1(M) junction and service area is now situated. The area is commonly known
as Bignalls Corner after Bignalls Garage which was once situated at the crossroad junction.
In May 1956, Rt Hon. Harold Watkinson, Minister of Transport and Civil Aviation, pronounced that the Government intended to transform the A1 into a major north-south
road designed to cope with modern traffic conditions.
This plan affected the entire stretch of the A1 and so it was not until May 1973 that the new motorway between South Mimms and Roestock at junction 2 was opened
as the A1(M). The 2 lane motorway reached a bottleneck at Hatfield where it went down to a single track carriageway through Hatfield along Comet Way and
through to Stanborough and Lemsford. It was not until 1986 that the A1(M) continued north of Roestock to Stanborough.
Local Junction Names
1 Bignalls Corner | Bignalls Garage was located here
2 Roestock | Area is known as Roestock
3 Roehyde | Roehyde Farm was located near to junction
4 Oldings Corner | Jack Oldings factory was located on Tesco site.
The M25 was originally planned to be two motorways, with the M16 outer orbital in the north and the M25 in Kent and Surrey in the south. The
decision was made in 1975 to create one single motorway circling London.
The M25 was constructed in sections and as each section was completed it was opened, each section was designated an A Road number until the whole sphere
was completed. Construction began on junctions 23 (South Mimms) to 24 (Potters Bar) in May 1973, this section was opened in September 1975
designated the A1178. This was the first section of the M25 to be opened! Work began on Junctions 24 to 25 in June 1979, it finally opened in June 1981.
I did read somewhere that the route of the M25 around Potters Bar was mainly down to Wrotham Park. Lady Byng of Wrotham park
objected to the route of the M25 passing so close to her grounds and so requested the queen intervene to re-direct the route. I am
not too sure how true this is and cannot remember where I heard this information from.
The M25 was completed in October 1986 with the linking of Junctions 22 (London Colney) to 23 (South Mimms)
The Motorway Archive
Ordnance Survey Maps