Region: Eastern
A(1)M Part of the A1 Strategic North - South Link
Statistics and options.
| Section | Construction started | Opened to traffic |
| South Mimms to Roestock (J1 to J2) | ? | May 1979 |
| Roestock to Stanborough (J2 to J4) | April 1984 | December 1986 |
| Stanborough to Welwyn (J4 to J6) | ? | May 1973 |
| Stevenage By-pass (J6 to J8) | ? | May 1962 |
| Baldock By-pass (J9 to J10) | ? | July 1967 |
| Alconbury to Peterborough (J13 to J17) | May 1996 | October 1998 |