Tony Blair is a narcissist with a messiah complex who lives a tragic life, according to former friend Robert Harris.

The best-selling author, a once close confidant of the former Prime Minister who has since become a fierce critic, lashed out at Mr Blair for turning his back on Parliament once he quit as PM to go and "hang out with a lot of rich people in America".

In his latest attack on the former Labour leader, he also holds up Lord Mandelson, who has been known to associate with a super-rich crowd, as a paragon of plain living and frugality compared to ex-premier.

Mr Harris, a former political journalist, is the author of The Ghost, a book turned into a film about a former British prime minister who faces being hauled in front of the International Criminal Court for war crimes, which he previously described as being somewhere "between reality and fiction".

Asked about Mr Blair's life today, he told Total Politics: "I find it tragic. I think it's presumptuous of me to say so but I can't believe there isn't an element of tragedy that he himself feels, that a relatively young man in political terms should cut himself off from British democracy ... because he could have had one of those 19th-century careers and come back, as Foreign Secretary or party leader, but he turned his back on it. I cannot understand someone who tasted that kind of role and fought for it, turning their back on it."

He added: "Who knew he would become a great friend of George Bush and would want to keep bombing people and would be so passionately interested in making money and live this strange life with the billionaire super-rich on yachts and private jets?"