"Public Men, Mr Birling, have responsibilities as well as privileges"


Contrast is used by Priestley when he remind Birling of his "responsibilities" as well as his "privilege".  By placing "responsibilities" first perhaps he is insinuating that Birling has forgotten this aspect, and instead is only concerned with his "privilege" (something that his actions certainly would attest). 
This quote reminds us of the issues present in both the society of Priestley and the society in which the text was set in, in which there were those with privilege but for whom responsibility did not seem important. This attitude therefore furthering the gulf between the lower and upper classes.