A new number plate is issued every six month.  The current known format that has been in place since Septebmer 2001 and uses a zero or a five to indicate which half of the year the plate was issued. This is known as 'age identifiers'.   For example 2002 would be shown as 02 and the second half of the year always issued in September would be 52.  The plate is prefixed with two letters before the year which indicate the city of issue.  This is know as 'local memory tags'  For example a new car sold at the start of the year in 2002 in Enfield would have a number plate of EN02.  Three random letters are then assigned after this to complete the plate number.

In March 2010 the identifier changed to 10.  In September 2010 this will change to 60.  This prefixed 6 being used to shown the second half of 2010.  So in March 2011 we would have 11 and in September this would be 61.