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

Basic rules:

^[A-Z]{1,2}[0-9R][0-9A-Z]? [0-9][ABD-HJLNP-UW-Z]{2}$

Postal codes in the U.K. (or postcodes, as they’re called) are composed of five to seven alphanumeric characters separated by a space. The rules covering which characters can appear at particular positions are rather complicated and fraught with exceptions. The regular expression just shown therefore sticks to the basic rules.

Complete rules:

If you need a regex that ticks all the boxes for the postcode rules at the expense of readability, here you go:

^(?:(?:[A-PR-UWYZ][0-9]{1,2}|[A-PR-UWYZ][A-HK-Y][0-9]{1,2}|[A-PR-UWYZ][0-9][A-HJKSTUW]|[A-PR-UWYZ][A-HK-Y][0-9][ABEHMNPRV-Y]) [0-9][ABD-HJLNP-UW-Z]{2}|GIR 0AA)$

Source: https://www.safaribooksonline.com/library/view/regular-expressions-cookbook/9781449327453/ch04s16.html

Tested against our customers database and seems perfectly accurate.