Speed limit signs are usually circular with a red border and a black number on a white background. They inform you of the maximum legal speed you are permitted to drive in good conditions on that stretch of road.
The maximum speed, in miles per hour, at which traffic may travel, if it is safe to do so
The national speed limit for the type of road and class of traffic applies
Road marking used in conjunction with upright signs to indicate the speed limit
Entrance to a 20 mph zone in which traffic-calming measures may be encountered
End of 20 mph zone and start of 30 mph speed limit
Start of a speed limit at the boundary of a town or village
Start of motorway regulations, including the national speed limit (unless a different speed limit is signed)
End of road works and any temporary speed limit through those works
Area where speed cameras are in use
Length of road where 2 cameras are used to measure the average speed of a vehicle between 2 points