Has Osama Bin Laden been dead for seven years - and are the U.S. and Britain covering it up to continue war on terror?
The last time we heard a squeak from him was on June 3 this year.
The world's most notorious terrorist outsmarted America by releasing a menacing message as Air Force One touched down on Saudi Arabian soil at the start of Barack Obama's first and much vaunted Middle East tour.
Even before the new President alighted at Riyadh airport to shake hands with Prince Abdullah, Bin Laden's words were being aired on TV, radio and the internet across ever continent.
It was yet another propaganda coup for the 52-year-old Al Qaeda leader. In the audiotape delivered to the Arab news network Al Jazeera, Bin Laden said that America and her Western allies were sowing seeds of hatred in the Muslim world and deserved dire consequences.
It was the kind of rant we have heard from him before, and the response from British and U.S. intelligence services was equally predictable.
They insisted that the details on the tape, of the President's visit and other contemporary events, proved that the mastermind of 9/11, America's worst ever terrorist atrocity, was still alive - and that the hunt for him must go on.
Bin Laden has always been blamed for orchestrating the horrific attack - in which nearly 3,000 people perished - eight years ago this week. President George W. Bush made his capture a national priority, infamously promising with a Wild West flourish to take him 'dead or alive'.
The U.S. State Department offered a reward of $50million for his whereabouts. The FBI named him one of their ten 'most wanted' fugitives, telling the public to watch out for a left-handed, grey-bearded gentleman who walks with a stick.
Yet this master terrorist remains elusive. He has escaped the most extensive and expensive man-hunt in history, stretching across Waziristan, the 1,500 miles of mountainous badlands on the borders of Pakistan and Afghanistan.
Undeterred, Barack Obama has launched a fresh operation to find him. Working with the Pakistani Army, elite squads of U.S. and British special forces were sent into Waziristan this summer to 'hunt and kill' the shadowy figure intelligence officers still call 'the principal target' of the war on terror.
This new offensive is, of course, based on the premise that the 9/11 terrorist is alive. After all, there are the plethora of 'Bin Laden tapes' to prove it.
Yet what if he isn't? What if he has been dead for years, and the British and U.S. intelligence services are actually playing a game of double bluff?
What if everything we have seen or heard of him on video and audio tapes since the early days after 9/11 is a fake - and that he is being kept 'alive' by the Western allies to stir up support for the war on terror?
Incredibly, this is the breathtaking theory that is gaining credence among political commentators, respected academics and even terror experts.
Of course, there have been any number of conspiracy theories concerning 9/11, and it could be this is just another one.
But the weight of opinion now swinging behind the possibility that Bin Laden is dead - and the accumulating evidence that supports it - makes the notion, at the very least, worthy of examination.
The theory first received an airing in the American Spectator magazine earlier this year when former U.S. foreign intelligence officer and senior editor Angelo M. Codevilla, a professor of international relations at Boston University, stated bluntly: 'All the evidence suggests Elvis Presley is more alive today than Osama Bin Laden.'
Prof Codevilla pointed to inconsistencies in the videos and claimed there have been no reputable sightings of Bin Laden for years (for instance, all interceptions by the West of communications made by the Al Qaeda leader suddenly ceased in late 2001).
Prof Codevilla asserted: 'The video and audio tapes alleged to be Osama's never convince the impartial observer,' he asserted. 'The guy just does not look like Osama. Some videos show him with a Semitic, aquiline nose, while others show him with a shorter, broader one. Next to that, differences between the colours and styles of his beard are small stuff.'
There are other doubters, too. Professor Bruce Lawrence, head of Duke University's religious studies' department and the foremost Bin Laden expert, argues that the increasingly secular language in the video and audio tapes of Osama (his earliest ones are littered with references to God and the Prophet Mohammed) are inconsistent with his strict Islamic religion, Wahhabism.
He notes that, on one video, Bin Laden wears golden rings on his fingers, an adornment banned among Wahhabi followers.
This week, still more questions have been raised with the publication in America and Britain of a book called Osama Bin Laden: Dead or Alive?
Written by political analyst and philosopher Professor David Ray Griffin, former emeritus professor at California's Claremont School of Theology, it is provoking shock waves - for it goes into far more detail about his supposed death and suggests there has been a cover-up by the West.
The book claims that Bin Laden died of kidney failure, or a linked complaint, on December 13, 2001, while living in Afghanistan's Tora Bora mountains close to the border with Waziristan.
His burial took place within 24 hours, in line with Muslim religious rules, and in an unmarked grave, which is a Wahhabi custom.
The author insists that the many Bin Laden tapes made since that date have been concocted by the West to make the world believe Bin Laden is alive. The purpose? To stoke up waning support for the war on terror in Iraq and Afghanistan.
To understand Griffin's thesis, we must remember the West's reaction to 9/11, that fateful sunny September day in 2001. Within a month, on Sunday, October 7, the U.S. and Britain launched massive retaliatory air strikes in the Tora Bora region where they said 'prime suspect' Bin Laden was living 'as a guest of Afghanistan'.
This military offensive ignored the fact that Bin Laden had already insisted four times in official Al Qaeda statements made to the Arab press that he played no role in 9/11.
Indeed, on the fourth occasion, on September 28 and a fortnight after the atrocity, he declared emphatically: 'I have already said I am not involved. As a Muslim, I try my best to avoid telling a lie. I had no knowledge... nor do I consider the killing of innocent women, children and other humans as an appreciable act.'
Within hours of the October 7 strikes by the U.S. on Tora Bora, Bin Laden made his first ever appearance on video tape. Dressed in Army fatigues, and with an Islamic head-dress, he had an assault rifle propped behind him in a broadly lit mountain hideout. Significantly, he looked pale and gaunt.
Although he called President George W. Bush 'head of the infidels' and poured scorn on the U.S., he once again rejected responsibility for 9/11.
'America was hit by God in one of its softest spots. America is full of fear, from its north to its south, from its west to its east. Thank God for that.'
Then came a second videotape on November 3, 2001. Once again, an ailing Bin Laden lashed out at the United States. He urged true Muslims to celebrate the attacks - but did not at any time acknowledge he had been involved in the atrocity.
And then there was silence until December 13, 2001 - the date Griffin claims Bin Laden died. That very day, the U.S. Government released a new video of the terror chief. In this tape, Bin Laden contradicted all his previous denials, and suddenly admitted to his involvement in the atrocity of 9/11.
The tape had reportedly been found by U.S. troops in a private home in Jalalabad, Afghanistan, after anti-Taliban forces took over the city. A label attached to it claimed that it had been made on November 9, 2001.
The tape shows Bin Laden talking with a visiting sheik. In it, he clearly states that he not only knew about the 9/11 atrocities in advance, but had planned every detail personally.
What manna for the Western authorities! This put the terrorist back in the frame over 9/11. The Washington Post quoted U.S. officials saying that the video 'offers the most convincing evidence of a connection between Bin Laden and the September 11 attacks'.
A euphoric President Bush added: 'For those who see this tape, they realise that not only is he guilty of incredible murder, but he has no conscience and no soul.'
In London, Downing Street said that the video was 'conclusive proof of his involvement'. The then Foreign Secretary, Jack Straw, added: 'There is no doubt it is the real thing. People can see Bin Laden there, making those utterly chilling words of admission about his guilt for organising the atrocities of September 11.'
Yet Professor Griffin claims this 'confessional' video provokes more questions than answers. For a start, the Bin Laden in this vital film testimony looks different.
He is a weighty man with a black beard, not a grey one. His pale skin had suddenly become darker, and he had a different shaped nose. His artistic hands with slender fingers had transformed into those of a pugilist. He looked in exceedingly good health.
Furthermore, Bin Laden can be seen writing a note with his right hand, although he is left-handed. Bizarrely, too, he makes statements about 9/11 which Griffin claims would never have come from the mouth of the real Bin Laden - a man with a civil engineering degree who had made his fortune (before moving into terrorism) from building construction in the Middle East.
For example, the Al Qaeda leader trumpets that far more people died in 9/11 than he had expected. He goes on: 'Due to my experience in this field, I was thinking that the explosion from the gas in the plane would melt the iron structure of the building and collapse the area where the plane hit and all the floors above it only. That is all we had hoped for.' (In reality the Twin Towers' completely fell down).
The words of the true Bin Laden? No, says Griffin, because of the obvious mistakes. 'Given his experience as a contractor, he would have known the Twin Towers were framed with steel, not iron,' he says.
'He would also known that steel and iron do not begin to melt until they reach 2,800 deg F. Yet a building fire fed by jet fuel is a hydrocarbon fire, and could not have reached above 1,800 deg F.'
Griffin, in his explosive book, says this tape is fake, and he goes further.
'A reason to suspect that all of the post-2001 Bin Laden tapes are fabrications is that they often appeared at times that boosted the Bush presidency or supported a claim by its chief 'war on terror' ally, British Prime Minister Tony Blair.
'The confession tape came exactly when Bush and Blair had failed to prove Bin Laden's responsibility for 9/11 and both men were trying to win international public support, particularly in the Islamic world, for the anti-terrorist campaign.'
Griffin suggests that Western governments used highly sophisticated, special effects film technology to morph together images and vocal recordings of Bin Laden.
So if they are fakes, why has Al Qaeda kept quiet about it? And what exactly happened to the real Bin Laden?
The answer to the first question may be that the amorphous terrorist organisation is happy to wage its own propaganda battle in the face of waning support - and goes along with the myth that its charismatic figurehead is still alive to encourage recruitment to its cause.
As for the matter of what happened to him, hints of Bin Laden's kidney failure, or that he might be dead, first appeared on January 19, 2002, four months after 9/11.
This was when Pakistan's President Pervez Musharraf told America's news show CNN: 'I think now, frankly, he is dead for the reason he is a kidney patient. The images of him show he is extremely weak.'
In his book, Professor Griffin also endorses this theory. He says Bin Laden was treated for a urinary infection, often linked to kidney disease, at the American Hospital in Dubai in July 2001, two months before 9/11. At the same time, he ordered a mobile dialysis machine to be delivered to Afghanistan.
How could Bin Laden, on the run in snowy mountain caves, have used the machine that many believe was essential to keep him alive? Doctors whom Griffin cites on the subject think it would have been impossible.
He would have needed to stay in one spot with a team of medics, hygienic conditions, and a regular maintenance programme for the dialysis unit itself.
And what of the telling, small news item that broke on December 26, 2001 in the Egyptian newspaper Al-Wafd? It said a prominent official of the Afghan Taliban had announced that Osama Bin Laden had been buried on or about December 13.
'He suffered serious complications and died a natural, quiet death. He was buried in Tora Bora, a funeral attended by 30 Al Qaeda fighters, close members of his family and friends from the Taliban. By the Wahhabi tradition, no mark was left on the grave,' said the report.
The Taliban official, who was not named, said triumphantly that he had seen Bin Laden's face in his shroud. 'He looked pale, but calm, relaxed and confident.'
It was Christmas in Washington DC and London and the report hardly got a mention. Since then, the Bin Laden tapes have emerged with clockwork regularity as billions have been spent and much blood spilt on the hunt for him.
Bin Laden has been the central plank of the West's 'war on terror'. Could it be that, for years, he's just been smoke and mirrors?