Using special characters in Views contextual filters

I was trying to grab a taxonomy term through a Views Contextual filter in Drupal, but it wasn’t working because the term contained an ampersand. (& character)

Turns out you need to urlencode any special characters (such as ampersands) twice.

So the following term:

Mr&Mrs

Should be sent like this

Mr%2526Mrs

25 is the percent sign. 26 is the actual characters you want to send to the contextual filters, in my case an ampersand.