Wikipedia
Twang!! is a musical with music and lyrics written by Lionel Bart and a book by Bart and Harvey Orkin, with assistance from Burt Shevelove. The piece was a spoof of the character and legend of the outlaw Robin Hood. It was a disastrous box-office failure and cost Bart his personal fortune.
After a preview in Manchester, Twang opened at the Shaftesbury Theatre in London's West End on 20 December 1965 and closed on 29 January 1966 after just 43 performances, receiving scathing reviews and playing to mostly empty houses. Bart produced it with Bernard Delfont and John Bryan, and Joan Littlewood directed but quit before it opened. She was replaced by Shevelove and Bart. Twang!! is remembered as "the most expensive flop" in West End history up to that time.