This will probably be a more controversial choice than my other British heroes, but Stead, for me, was the epitome of what investigative, campaigning journalists used to be about. His "Maiden Tribute of Modern Babylon" campaign against child prostitution in London led directly to the government of the time raising the age of consent from 12 to 16.
Stead was a confirmed pacifist, but one who understood that peace comes from strength. His final campaign eventually forcing Britain to upgrade the RN in the face of increasingly powerful rivals.
Stead died aboard the Titanic where he was reported to have helped women and children to safety before retiring to the smoking room and awaiting his fate in a leather chair while reading a book.
He has been referred to as "the father of modern journalism" though I, personally, can see little connection between today's value free, morally bankrupt, post-modern relativist journalism and Stead's personal crusading.