Unfortunately colour blindness does play a part in our licensing as well. The medical for pilots and controllers as far as i know is the same, However there is a class 1 and 2 medicals(both vary) However i have known people that were colour blind (or so they thought ) to be found not to be, as under controlled enviroments, light can play tricks. Also there are different levels of colour blindness. Best way for sure is to contact the medical branch of the CAA at Gatwick.