Ali had published the first three titles in his Islam Quintet of novels, which chart the encounter between Islam and western Christendom over the centuries, when 9/11 happened and the U.S. government led by then President George W. Bush took the decision to invade both countries.

"George Bush was quite an inspiration to me to start writing non-fiction again," Ali told a news conference at the Semana Negra book festival in Gijon, northern Spain, which draws one million people a year.

"My publishers would ask me, 'When are you going to finish the Quintet?' and I would say, 'Ask George Bush. Is he going to make a war on a third country?"

Following 9/11, Ali penned The Clash of Fundamentalisms, a non-fiction work which details the history preceding the attacks on New York and Washington and explores the political history of Islam as background.

He has also recently written critically of the alliance between the United States and his native Pakistan in The Duel: Pakistan on the Flight Path of American Power, which complements dozens of political works and polemics authored by Ali since he was a radical student activist in 1960s Britain.

Ali says many in Britain have criticised him for delving into fiction, saying it detracts from his non-fiction writing.

"It isn't a contradiction to write fiction, non-fiction," he said. "It's the same person writing this, but in different ways. Different things come out of people as they are writing fiction and different things are important when writing history or biography."

CELEBRITY CULTURE

He said that the Obama administration had adopted a different approach to the war in Iraq from its predecessors, but said it would be a mistake to believe a single president could make a radical change across the board.

We are in a world which is very obsessed with individuals, celebrity culture," Ali said. "The mistake is to think of the President of the United States as a celebrity."

Ali likened U.S. presidents to Caesars, or emperors of Ancient Rome.

"Of course, there are always different types of Caesars. You can be a Caesar like Caligula, which is Bush, or like Augustus, which is Obama," he said.

"But your function is the same, to preserve and protect the interests of the empire that you rule."

Ali added that an obsession with celebrity lifestyles had led media to focus on particular bankers in coverage of the world financial and economic crisis.

"To encourage attacks on individual bankers totally masks the reality of a system which has created these guys and the politicians who have passed laws to make it possible."

Reuters