George Tower,
In Europe the whole thing is governed by slot times, so the volumes are controlled by ATC themselves. So it is not possible for it to become-
" seriously overstretched to almost dangerous levels. "
If you think Gatwick is busy, try Chicago or Atlanta!
I have personally flown in South Africa, The US and Europe and always found the controlling to be of a high standard in all three countries.
Problem in South Africa is that the controllers aren't paid enough which results in a continual "Brain drain" of good controllers.
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