Book excerpt: The ghosts of Britain need a sanctuary. Castles with central heating, bogs drained for motorways, dismal forests cleared for car parks-there are few places left for a respectable ghost to haunt. Humphrey the Horrible (actually his name is simply Humphrey-he added "the Horrible" to help himself become horrible) is a small, mostly unsuccessful ghost in a family of ghastly ghouls. His mother worries. But Humphrey has enough pluck to befriend a smart, politically aware schoolboy, Rick Henderson, who is willing to take the ghosts' cause right to the top, to number 10 Downing Street-home of the Prime Minister.