hell no chas ain't a fifth beatle but bill could be.....

Maybe there were several different people called the "fifth Beatle". Maybe throughout the Beatles musical era, or even later on? I think there was defiantly a "fifth Beatle" way before George Martin. And as the group progressed as a band, so did each member of it. Musically and personally. Stronger bonds would be made between the boys and some bonds would wear off. (Pete Best for example) They could of called him the fifth Beatle at some point in time and then obviously boot him off, since he was no longer apart of the band after awhile. But me personally, I think George Martin was the "real" fifth Beatle all a long. But also with the fact, that he was never the first. Who really knows? Just like DaveRam said, the fifth Beatle could of been the fans.  
So it could of been anybody.

For me, it kind of depends on what you're looking at  -  musically, direction-wise (hey, I know that's not a word), historically (in terms of helping them become who they became), visually (they had so many iconic images, from Astrid in Hamburg right through to Let it Be), so I'm gonna cop out completely and say, well, I can't narrow it down!!

So I voted, there is no 5th Beatle, but what I really mean is there is no single 5th Beatle, just about a hundred or so.