What is the plot structure?

The construction of Look Back in Anger is that of an old-fashioned well-made play in the tradition of Henrik Ibsen, August Strindberg, Tennessee Williams, or most of Osborne's contemporary commercial playwrights. There is one plot developed over three acts (the expected number in 1956), and the basic plot device is ancient: misalliance in marriage compounded by a love triangle. There is some exposition that has been characterized as clumsy, such as when Jimmy tells Alison, to whom he has been married three years, how his business had been financed. Some plot devices stand out as the author's contrivances, such as Cliffs exit in Act I to buy cigarettes, and his unconvincing reasons for returning a couple of minutes later just as Alison is about to tell Jimmy that she is pregnant; the telephone call from Helena prepares for the Act I curtain and a phone call saying Hugh's mother is dying prepares the Act U, Scene 1 curtain. The end of Act JJ, Scene 2, with the two women left looking at each other, has been viewed as artificial. Osborne's innovations were not in form but rather in character, language, and passion which, for the most part mask the clumsy mechanics when the play is being acted.