who is this guy? be afraid England...!!!

Ali or Robinson. They both have had a huge influence towards race related issues, were great in their sports, and Ali has even contributed some new cliches to the english language like "float like a butterfly, sting like a bee"

I think it comes down to a straight fight between Ali and Pele. Probably going to Ali. Although I wonder if his wasn't a greater influence outside of sport, rather than inside. In which case it might actually be Marc Bosman.

Most influential is Michael Jordan, transcended sport for the sake of consumerisim. Great athlete, soulless man, icon.