The London Independent has an

The London Independent has an article about authors commanding higher and higher advances:

But few British novelists can command the tens of millions paid out to America’s top thriller writers. “In Britain, only JK Rowling is at that sort of level,” says one agent, “she is possibly the biggest brand in the world and can demand any price now. But when she started out she got only £100,000 for the American rights to Harry Potter. At the time it seemed like a lot, now it looks like a bargain.”