What role does the Queen play in this story?

The Queen facilitates the conclusion of the story. Without her assistance, Sophie and the BFG would have had a much more difficult time trying to stop nine raging giants. The Queen gives Sophie, an orphan, and the BFG, a giant, instant legitimacy in her world. She is respectful and kind to them, and treats them well, even though they are the ultimate outsiders. She verifies their story and then sets about making sure they can accomplish their goal.