"Can't stay long, Mother," he said. "I'm up front, the prefects have got two compartments to themselves-" "Oh, are you a prefect, Percy?" said one of the twins, with an air of great surprise. "You should have said something, we had no idea." "Hang on, I think I remember him saying something about it," said the other twin. "Once-" "Or twice-" "A minute-" "All summer-" "Oh, shut up," said Percy the Prefect."