The Duke of Sussex addressed his complicated relationship with the UK's tabloids in a new ITV1 documentary, "Tabloids on Trial."

As Harry put it, anything he says about his father and the rest of the royal fam will likely be turned into a "torrent of abuse" from the British media ... which he feels has been a "central piece" in the ongoing feud with his kin.

However, he says that won't make him back down, and he remains steadfast in his mission to legally take on the tabs. Interestingly, he says he's still hoping his family will join him in the battle.

Both Harry and Meghan have made a point of calling out the royal family for being in bed with tabloids ... using them to make themselves look good, while looking the other way when they wrote negative stories about Meghan.

While Harry danced around directly commenting on the royal family's lack of action in fighting the media, he did note that his win in last year's phone hacking case helped show people the truth ... and he felt vindicated after experiencing "paranoia, fear and distrust."

He also says his mother, the late Princess Diana, motivated him in this legal battle ... as he believes she struggled similarly during her lifetime.

Harry says, "Probably one of the first people to be hacked and yet still today, the press, the tabloid press very much enjoy painting her as being paranoid. But, she wasn't paranoid, she was absolutely right about what was happening to her."