Rowling decided to make the Potter ebooks DRM-free, because she “personally believes that if someone’s bought an ebook they ought to be able to read it on their Sony Reader, their Kindle, their iPad, their PC”, said Redmayne – and so far, piracy has not been much of an issue. “We’re going DRM-free but have put watermarks on the books which can trace individual files back to individual sales. It was very interesting. When we first went live we saw a few files go up, and then there was a real backlash,” he said. “People were going ‘really? Finally they’ve done what we asked for and you go and stick it up there? And what are you, the stupidest pirate in the world, as they’ll know who’s done it?’ And they came down again.”