Geoffrey G. Butler is the uncle and mentor of a man who was a prominent what? 
Geoffrey G. Butler:  He was uncle of and mentor to Rab Butler, and was an early sponsor of Liddell Hart, a former student who would upon the senior Butler's death that 'I have never had a better friend, in every sense of the word’. Rab Butler: Richard Austen Butler, Baron Butler of Saffron Walden, (9 December 1902 – 8 March 1982), generally known as R. A. Butler and familiarly known from his initials as Rab, was a prominent British Conservative politician. "
British Conservative politician