Who is The English Visitor from The Jewel in the Crown and what is their importance?

The English Visitor is the unnamed narrator and fictional author of the book who is investigating the incident at the Bibighar Gardens several years after the events. He is the guest of Lady Chatterjee, who introduces him to some of the people who were present at the time and puts him in touch with others who have since left Mayapore. He receives from her some of Daphne's letters and her journal, from which he learns the truth about Bibighar.