Prince Harry's memoir publisher said the Duke's book was the fastest-selling non-fiction book of all time.
The Duke of Sussex’s autobiography recorded sales figures of 400,000 copies so far across hardback, ebook and audio formats on its first day of publication, according to publisher Transworld Penguin Random House.
Larry Finlay, the publisher's managing director, said: "We always knew this book would fly, but it is exceeding even our most bullish expectations.
