What should you do?
If you need to stop, check mirrors, signal and slow down gradually to enter the lay-by.
How to recognise it
A blue rectangle with a white P and 100m below.
Common confusion
The blue P here indicates a lay-by or parking area, not a mandatory instruction.
Explanation written by the My Driving Test editorial team using the Department of Transport Traffic Signs Manual conventions and the RSA Rules of the Road.
