"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.