Prince Harry has revealed that he deleted many details about his father and brother from his autobiography “Spare” which sold 1.4 million English-language copies on its first day in the UK, United States, and Canada.

In an interview with The Telegraph, he said he was worried about publishing details about the lives of his father, King Charles III, and his brother, William, Prince of Wales.

Harry noted that he has enough material to write “another book” ; however, he “cut the memoir in half to spare my family.”

He added that there is some information he revealed to his ghostwriter JP Moehringer “for context” but there was “absolutely no way” it could be included in the memoir.

"It could have been two books, put it that way," he said, noting that the first draft was 800 pages, which is double the final 400-page manuscript.

"And there were other bits that I shared with JR, that I said: 'Look, I'm telling you this for context but there's absolutely no way I'm putting it in there.'"

He continued, “But there are some things that have happened, especially between me and my brother, and to some extent between me and my father, that I just don't want the world to know. Because I don't think they would ever forgive me” if they are disclosed.

“Now you could argue that some of the stuff I've put in there, well, they will never forgive me anyway.

“But the way I see it is, I'm willing to forgive you for everything you've done, and I wish you'd actually sat down with me, properly, and instead of saying I'm delusional and paranoid, actually sit down and have a proper conversation about this, because what I'd really like is some accountability. And an apology to my wife.”

"Spare" was published in a total of 16 languages worldwide and released simultaneously in print and digital formats in North America by Random House US and Random House Canada, and in the United Kingdom by Transworld.

An unabridged audio edition of the book, read by Harry himself, was also published by Penguin Random House Audio.

The first US printing of Spare was two million copies, however, the book has now gone back to press for additional copies to meet demand, according to Penguin Random House.

Bookshops in the UK opened early Tuesday to offer Harry’s book although buyers were sparse after the extensive leaks ahead of publication.

The blockbuster publication comes as the royal family prepares for the coronation of Harry's father King Charles III on May 6.

The royal family has not commented on the book.