London: It was not Osama bin Laden who came up with the 9/11 plot, a new book has claimed which also says that he had initially dismissed the plan.

When the strike was first proposed to him in 1996 the al-Qaeda leader was 'noncommittal' and refused to give his backing.

It was not until three years later before he could be brought around and another five years before the deadliest attack on US soil since Pearl Harbour eventually took place.

The book, titled 'The Hunt for KSM: Inside the Pursuit and Takedown of the Real 9/11 Mastermind, Khalid Sheikh Mohammed', also gives the first in depth account of the problems the FBI and CIA had hunting down al-Qaeda after 9/11.

It includes one farcical raid where a key suspect who was severely wounded nearly died when after almost being dropped 20ft onto airport runway by bungling agents.

The book, explains that it was not actually bin Laden who came up with the idea for the September 11 plot, a newspaper reported.

Instead it was brought to him by Mohammed and Abdul Hakim Murad, one of those behind the Manila Air plot to plant bombs aboard a dozen US commercial aircraft.

During a meeting in Pakistan in 1996 between the three of them Murad was the one to suggest crash landing aircraft into the CIA headquarters or perhaps a nuclear reactor.

"(Murad said) If you did this you needn't go through the precise and exacting process of building bombs. You didn't need bombs at all," the book says.

 "Bin Laden was noncommittal. He told KSM (Mohammed) heappreciated the ideas and would give them due consideration", it says.

It took three years before bin Laden changed his mind, but even then he only backed a 'slimmed down' version of the plan using four or five planes which turned into the horror that emerged on 9/11, according to the book.

In 'The Hunt for KSM', authors Terry McDermott and Josh Meyer also lay out how the pursuit of Mohammed was badly hampered by bickering between the CIA and the FBI.