Doctor Who: 13 Cool Details Russell T Davies Just Revealed About The Stolen Earth & Journey's End
5. The Duplicate Doctor Almost Led The Shadow Proclamation Into War Against The Daleks
In Journey's End, the duplicate version of the Doctor is shown to be a lot more reckless than the original - mainly due to his mixture of human and Time Lord DNA - and at one point, Davies was planning to take this idea a lot further than he eventually did.
According to the writer, there were some early plans to have the "Blue Suit Doctor" fly back to the Shadow Proclamation, recruit them, and then lead them into a massive war against the Daleks. This was intended to illustrate how wild the duplicate Doctor was, and why he needed Rose's kinder and more empathic personality in his life.
In the end, the episode's quicker and cheaper way of making that point was to have the duplicate Doctor fashion a gun to use against the Daleks, with Davies adding that he carried this "Bad Doctor" idea into the Time Lord Victorious.