Richard Bird (1948–1993) worked under Ken Briggs at the National Theatre 1972 to 1975. In 1975 Bird became resident head of graphics at the theatre’s new South Bank location. Some of these posters were also worked on by Michael Mayhew, who took over from Bird in 1986.
Further reading: Rick Poynor National Theatre Posters: A Design History, which can be found in the Reading Room