UK_postcode_regex.txt

/* UK Postcode Pattern
 * < Outward Code > < Inward Code>
 * <AREA><DISTRICT> <SECTOR><UNIT>
 * AREA = 1 or 2 chars 
 * DISTRICT = (one or 2 digits) or (digit then letter)
 * Space (optional)
 * SECTOR = digit
 * UNIT = 2 chars
 * 
 * $postcode_regex = '/^([A-Z]{1,2})([0-9]{1,2}|[0-9][A-Z])\s?([0-9])([A-Z]{2})$/i';
*/


$postcode_regex='/^'.                           // Start of postcode
                '([A-Z]{1,2})'.                 // AREA = 1 or 2 chars
                '([0-9]{1,2}|[0-9][A-Z])'.      // DISTRICT = (one or 2 digits) or (digit then letter)
                '\s?'.                          // Space (optional)     
                '([0-9])'.                      // SECTOR = digit
                '([A-Z]{2})'.                   // UNIT = 2 chars
                '$/';                            // End of Postcode