What is the main conflict in The Wasp Factory: A Novel by Iain Banks?

The novel by Iain Banks, "The Wasp Factory" tells the story of 16-year-old Frank Cauldhame. He lives on an island (unnamed) off the cost of Scotland with his father, Angus. Frank has no official status. He has no birth certificate and no national insurance card. At the direction of his father, he must tell anyone who asks that he is the nephew of Angus—not the son.