Former British Prime Minister Tony Blair says the 21st century may well be marked by a struggle over religious or cultural ideology.
In an interview with Kim Hill on Radio New Zealand National to mark the publication of his memoirs, Mr Blair says he's extremely interested in bringing different religious faiths together.
Despite what some conspiracy theorists may claim, he says, religion played no part in any of his foreign policy decisions, such as backing the US invasion of Iraq.
Mr Blair says the reason he made the decisions he did was that he thought they were right at the time, and the world changed after the 9/11 attacks.
Mr Blair told the programme that former Iraqi leader Saddam Hussein was in breach of UN resolutions on weapons of mass destruction (WMD).
"He'd used WMD, the only person to have done it, killed thousands of his own people by the use of chemical weapons, so it was extremely important then to send that signal out and make that signal count, which we did."
He says the invasion of Iraq would not have gone ahead if the 9/11 attacks hadn't happened, and it was decided that a strong line must be taken in respect of those who had committed the atrocity.