RegEx for matching UK Postcodes

Question

I\'m after a regex that will validate a full complex UK postcode only within an input string. All of the uncommon postcode forms must be covered as well as the usual. For in

Answer 1

First half of postcode Valid formats

• [A-Z][A-Z][0-9][A-Z]
• [A-Z][A-Z][0-9][0-9]
• [A-Z][0-9][0-9]
• [A-Z][A-Z][0-9]
• [A-Z][A-Z][A-Z]
• [A-Z][0-9][A-Z]
• [A-Z][0-9]

Exceptions
Position 1 - QVX not used
Position 2 - IJZ not used except in GIR 0AA
Position 3 - AEHMNPRTVXY only used
Position 4 - ABEHMNPRVWXY

Second half of postcode

• [0-9][A-Z][A-Z]

Exceptions
Position 2+3 - CIKMOV not used

Remember not all possible codes are used, so this list is a necessary but not sufficent condition for a valid code. It might be easier to just match against a list of all valid codes?