The House will forgive me for quoting five democratic questions that I have developed during my life. If one meets a powerful person — Rupert Murdoch, perhaps, or Joe Stalin or Hitler — one can ask five questions: what power do you have; where did you get it; in whose interests do you exercise it; to whom are you accountable; and, how can we get rid of you? Anyone who cannot answer the last of those questions does not live in a democratic system.

Tony Benn
Tony Benn (1925-2014) British politician, writer, diarist
Speech, House of Commons (16 Nov 1998)
    (Source)

Benn used this set of questions -- often with different examples -- on multiple occasions.