The B630 is a contender for one of the shortest classified roads, at 285 yards long. It exists solely to bridge the gap between the A69 and B6318 roads at Greenhead in Northumberland. The road was built in the 1980s to link the two roads following the construction of the A69 Greenhead bypass. The original route of the A69 has now been blocked off in both directions (but is still obvious from a map); the B630 is not as steep as the old road and does not need to cross the railway line.
Starting on the A69 bypass the B630 (whose number is given on the signs) heads gently downhill round a left-hand bend into Greenhead. There's barely time to pick up speed before we pass the 30 signs and then end at a T-junction on the B6318, which here follows the original line of the A69 - the TOTSO on that road immediately to the left shows the old priorities.