Single or double yellow lines indicate that a waiting restriction is in force.
Double yellow lines indicate that there no waiting is permitted at any time.
A single yellow line indicates that no waiting is permitted during certain periods. Yellow signs in the vicinity will indicate the days and times in which the restrictions are in force. If there are no days mentioned on the sign then the restrictions are in force every day including weekends and bank holidays.
Whilst no waiting is permitted on a waiting restriction, you are allowed to briefly pick up and set down passengers. Stopping on yellow lines is permitted for vehicles engaged in continuous loading and unloading of heavy goods.