George H. W. Bush

 was a President of the United States who, according to the Eighth Doctor, served between Ronald Reagan and Bill Clinton. (PROSE: Interference - Book One)

Behind the scenes
Bush's forenames weren't given in Interference - Book One, but the common-sense interpretation of the passage is that the author was referencing the real-life President George H. W. Bush. His son, George W. Bush, would be elected president a year after Interference was published.