The law states that,
You must not alter, rearrange or misrepresent the letters or numbers
Characters must not be moved from one group to the other
(e.g. A242 ABC must not be displayed as A242A BC).
To simply explain the regulations, looking at the plate below:-
The 'Characters' are the individual letters and numbers. The 'Space between characters' refers to the spaces within a group of characters together, in this case A555 is one group and WOW is another group. The 'Space between groups' is thus the legal required space between those 2 groups of characters (shown as 33mm in the example)
Number Plates Fitted After 1st September 2001
Number plates fitted after 1 September 2001 must display characters that meet the dimensions shown below.
Characters Group 1
Height 79mm
Width (except Number 1 or letter I) 50mm
Stroke 14mm
Space between characters 11mm
Space between groups 33mm
Top bottom and side margins (minimum) 11mm
Space between vertical lines 19mm
Number Plates Fitted Before 1st September 2001
Number plates fitted before 1 September 2001 must display characters that meet the dimensions shown in one of the two groups below
Characters Group 1 Group2
Height 89mm 79mm
Width (Except Number 1 or letter I) 64mm 57mm
Stroke 16mm 14mm
Space between characters 13mm 11mm
Space between groups 38mm 33mm
Side margins (minimum) 13mm 11mm
Space between vertical lines 19mm 19mm
Display Of Vehicle Registration Marks On Imported Vehicles
(which have a restricted space for a standard sized number plate)
Certain imported vehicles may be permitted to display number plates with smaller characters if the vehicle does not have European Community Whole Vehicle Type Approval AND the vehicle's construction/design cannot accommodate standard size number plates