Why UK? Why do you do sh*t like this? Who registers a military aircraft with ZZ666?
Flying right now. While a huge 666 slide is going on here. You can't make this stuff up.
Just like DMVs have blocked out combinations for motor vehicle registrations; somebody should've said 'hey, this won't do' . Just like callsigns aren't totally up for grabs. I'm sure their logs are an interesting assortment then. What you tolerate, you encourage.
Guess the Brits are sick of humoring the demons playing dress up.