Resigned 8 April 1763 It is not disputed that Bute s successor Grenville took office as PM on 16 April 1763 But the 1911 Encyclopedia Brittanica gives Bute s date of resignation as 8 April 1763 And a calculation from the dates and figures provided by 10 Downing Street Total time as PM 317 days also indicates he resigned office 8 April And Marjie Bloy agrees on 8 April 1763 I m about to edit the dates in office If anyone reverts please provide credible references