jQuery Ketchup validator for UK postcodes

gistfile1.js

$.ketchup.validation(
    'ukpostcode',
    'Please enter a valid UK postcode',
    function(form, el, value){
        var tidyValue = value.replace(/\s+/g, '');
        var pattern = /^(GIR0AA)|((([A-PR-UWYZ][0-9][0-9]?)|(([A-PR-UWYZ][A-HK-Y][0-9][0-9]?)|(([A-PR-UWYZ][0-9][A-HJKSTUW])|([A-PR-UWYZ][A-HK-Y][0-9][ABEHMNPRVWXY]))))[0-9][ABD-HJLNP-UW-Z]{2})$/i;

        return pattern.test(tidyValue);
    }
);