In the seventies, he played the part of Markov Chaney in the stage production of 'Illuminatus!',
a 5 part, 8-hour psychedelic science-fiction rock-opera, directed by Ken Campbell.
'Illuminatus!' was based on 3 books written by Robert Anton Wilson and Bob Shea. It tells the tale of the conspiracy by the 'Illuminati', who attempt to order and control mankind, amongst others by dominating all the record companies, which is why only very dull music is produced.
Their arch enemies, at least as old as the Illuminati, are the Justified Ancients of Mummu (the JAMs). They are engaged in a secret war against the Illuminati and start their own record company to bring out good music.
The books, and the play, were a huge cult-success, mixing reality with fiction, using lots of sex and drugs and rock & roll, combined with occult matters, such as synchronicity and numerology - the number 23 plays an important role.
The stage production of 'Illuminatus!' opened in Liverpool, in '76, on the 23rd of November- David's birthday- and later moved to London. There it opened the Cottesloe Theatre at the Royal National Theatre, in the presence of HM Elisabeth II, Queen of England - quite a striking achievement for a completely subversive play.