I can't see a couple of measly colours, and I'm not allowed to fly IFR, and yet a bloke who can't see anything at all can fly!?
Seriously, that was only a little bit tongue-in-cheek. This smacks of a complete lack of joined up thinking from the CAA. Rather than restricting colour defective pilots to VFR daytime flying only, why not simply stipulate that they have to have a safety pilot with them? Or better yet, offer a 5 hour course for any lay-person with normal colour vision (e.g. the pilot's partner) to be allowed to fly as safety pilot for the purposes of assisting the PIC with all those things which require colour vision when flying IFR.
Hmpf.
TPK