Lennox Lewis, though there have been many.
Jimmy Wilde.
Flyweight champion from 1913 to 1921 I believe. Won the flyweight title in 1916 and kept until 1923, when the great Pancho Villa knocked him out in 7. He won 132 fights, lost only three, and scred 98 knockouts. For such a small man, (he never weight more than 107 pounds in any fight) Wilde had middleweight punching power.
I agree with Mace.... Jimmy Wilde, The Ghost With a Hammer in his Hand. Barely over 100 lbs in his prime but he would fight men as high as featherweight and went through his first 101 contests unbeaten.
He was the first official world flyweight champion and ended up with only four losses in 150 recorded fights and around 100 KO wins. I say recorded because fight records were sketchy in those days and Wilde claimed to have had over 700.
Jimmy Wilde and Joe Calazaghe
Joe Calazaghe
jimmy wilde is the best ever but if you want a more modern fighter then i would say Naz was the most talented but he never full filled his potential ,lennox i don't think of as british as he learnt to box in canada , so i go with calzaghe
ricky hatton in my opinion most would say lex lewis
Apparently steve bunce has hamed down as the best....im thinking lewis calzaghe or one of the oldies..?