|From:||Hatfield (N) (TL226104)|
|To:||Welwyn Garden City (TL238121)|
|Distance:||1.5 miles (2.4 km)|
|Meets:||A1(M), A1001, A414, B653, A1000|
|Former Number(s):||B653, B190|
|Old route now:||B653|
|Route outline (key)|
The Luton to just-north-of-Hatfield road was originally the B653, but got upgraded to an 'A' road in the late 1960s, becoming the A6129. The road from Stanborough to Welwyn Garden City, which had previously been the B190, also gained this number a few years later.
In the late 1980s, the A1(M) from junction 2 to the temporary terminal where the A6129 ended was built. The A6129 got a spur to the new junction 4, along the old A1, and then, when the A5 and A6 got renumbered through St Albans, the bit from the A1 to Luton got downgraded back to B653.
This left just the new spur along the old A1, and the bit from the former A1 junction to Welwyn Garden City's town centre. The road is now fully in zone 1 and meets the A1001 (itself taking part of the old A1) end-on at A1(M) junction 4.
It is now the most southerly A road with a number beginning with 6.