Duke of Edinburgh Assassinated or The Vindication of Henry Parkes

Duke of Edinburgh Assassinated or The Vindication of Henry Parkes is a 1971 Australian play written by Bob Ellis and Dick Hall. It followed Ellis' successful "The Legend of King O'Malley".
Background.
In 1970 Bob Ellis went to a party given by Gough Whitlam's secretary Dick Hall thinking he was going to be asked to write speeches for Whitlam. Instead Hall proposed they collaborate on a musical about the attempted assassination of Prince Alfred in Sydney in 1868. They wrote the play over weekends.
Productions.
It premiered at the Nimrod Theatre in 1971 directed by Aarne Neame. Reviewing the 1971 production the "Sydney Morning Herald" critic felt the second half was better than the first. The reviewer from "The Bulletin" said:
Slabs of factual research and transcription covering trials, commissions and interviews (fascinating in content, no doubt, but deadly dull as theatre) are interspersed with stretches of music-hall song-and dance routines in a desperately contrived effort to sugar the pill. But the pill sticks firmly in the throat. The authors are concerned with politics, not Parkes. They have produced a play without characters, a documentary dolled up as a theatrical event and a somewhat confusing documentary at that.
The play was also produced in Melbourne in 1972.