And why you might ask? Was it because Apple is against lefties? Nope. It's just because if you hold the phone in your left hand then you'll cover the top left hand corner of the phone which, for some reason, reduces the signal to zero.
Admittedly this is not every iPhone 4 but quite a few.
SO what was Steve Jobs response to this problem? "Just avoid holding it that way"
WOW, thanks so much. I couldn't have figured that out without your wisdom. I paid £500 for a phone that I have to hold awkwardly but hey, I will do whatever Steve Jobs says because I'm an idiot.