While Shaw wrote many plays, the one often considered a disguised critique of England's imperialist activities is "Major Barbara".
In this play, Shaw uses the character of Undershaft, a wealthy munitions manufacturer, to satirize the hypocrisy of the British Empire's supposed moral superiority while profiting from war and violence. He also explores themes of class, poverty, and the role of religion in a society grappling with the consequences of colonialism.
While Shaw never explicitly condemns British imperialism, the play's satirical tone and its exploration of the dark side of industrialization and war are widely interpreted as a critique of England's imperial ambitions.