Kenneth Branagh’s obsession with Larry Olivier’s career is becoming such a bizarre act of theatrical necromancy that it deserves to be turned into a drama. Sir Ken and Lord Olivier could be played by the same actor. The Entertainer, written for Larry in 1956 by John Osborne, presents us with a washed-up music-hall star, Archie Rice, who is supposed to symbolise Britain’s post-colonial decline.