Mr Birlings attitude towards the future

Although Birling and his wife are indeed middle-class, Priestley tells us in one of his stage directions (though it is never explicitly referred to in the play itself) that Sybil is “a rather cold woman and her husband’s social superior.” Birling is throughout the play ticked down by his wife: early in this act, for instance, for complimenting the servants on the meal in front of a guest. Sybil, presumably from a better social background than Birling, seems to be, in an imperious, passive way, the one in control of the marriage—and of her husband. Birling himself seems to have worked his way up to the middle classes (he is “provincial in his speech,” Priestley tells us in another stage direction, which might be another clue to his background) and, as he explains to Gerald, he is currently trying to see his way to a knighthood and therefore greatly improving his social position. In short, the Birlings have ambitions to move up the social scale.