The Duke of Sussex’s autobiography is the fastest-selling non-fiction book ever, recording figures of 400,000 copies so far across hardback, ebook and audio formats on its first day of publication.

Larry Finlay, managing director of Transworld Penguin Random House, said; “We always knew this book would fly but it is exceeding even our most bullish expectations.

“As far as we know, the only books to have sold more in their first day are those starring the other Harry (Potter).”

Queues of fans developed before shops opened at 12am Tuesday morning for the official release of the controversial memoir.

A handful of people waited outside the doors of WHSmith in London’s Victoria station to be one of the first to buy a copy of the book – which has made headlines across the world with bombshell revelations about the Royal Family and was leaked and sold early by some booksellers in Spain.

Crowds of photographers, camera operators and reporters captured the moment that the first customers were handed copies of the memoir.

Sarah Nakana, 46, was first to the till to buy her copy at just gone midnight, describing Prince Harry’s decision to write the book and tell his story as “incredibly courageous and brave”.

She said: “I’m excited to hear from Prince Harry about his life in his words.

“He has created a historical record of his life. He lived it. Only he knows what he endured and went through.

“I know for sure the UK media sensationalised some of the bits that make him look in the worst light and sell them the most papers.”

Other early customers included Professor Chris Imafidon, who purchased three copies, and two 20-year-old friends Ben Vu and Leigh Harper.