The B6420 Mansfield Road heading towards the A1
The B6420 is a short link running from from the Apleyhead grade-separated junction on the A1 east of Worksop to the A620 at Babworth west of Retford.
It was first classified in the early 1930s, and originally ran from a point on the A614 840 m southwest of its present starting-point. It was later cut back to the A1 and then rerouted to meet the new GSJ in 2007. As such the original western end of the B6420 is now closed to traffic and partly taken over by a field. Originally the road would have been wholly west of the A1 (which ran through Retford until the 1960s) and so in-zone.