Conspiracy theories about what happened on 9/11 began to circulate just days after the attacks, but in recent months they've become a phenomenon with up to 75 per cent of Americans believing their government hasn't told them the whole truth about that tragic day.
World Trade Centre janitor William Rodriguez was there when the aircraft struck the Towers and was decorated for his heroism in rescuing survivors.
Ahead of an appearance in Lewes, he speaks to Angela Wintle about the experience and the disturbing questions he's been asking ever since.
They still haunt his dreams, the ones who didn't get away. He hears their screams for help from the passenger lift, screams he heard as he fled from the stricken World Trade Centre for the very last time.
He sees the faces of his old pals from the Window on the World restaurant, people he met daily over breakfast, who never stood a chance on the 106th floor. He remembers the fixed looks in the eyes of the firefighters as they pushed past him up the stairwell, never to return.
William Rodriguez saved dozens of lives on 9/11, but it's the ones he didn't save he thinks about most.
But, of course, by rights, he shouldn't be here at all. Rodriguez, 45, was a janitor at the World Trade Centre, tasked with cleaning three stairwells in the North Tower. But on September 11, 2001, he overslept and was half an hour late for work.
Ordinarily, he would have been having breakfast in the staff kitchen 106 storeys up when the first aircraf hit at 8.46am. But the Fates were looking down on him that day and he'd only just entered the basement of the building.
"I was on B1 level, talking to my supervisor, when we suddenly heard a massive explosion," he says.
"It was so strong the walls began to crumble and the false ceiling fell on top of us.
"Then, seconds later, there was another explosion way above, which made the building sway from side to side. And this, we later discovered, was the first plane hitting the North Tower on the 90th floor."
Rodriguez became a national hero as a result of his actions that day and was honoured five times at the White House. But all that changed when he started asking some very awkward questions.
Why had he heard a massive explosion from the basement seconds before the first aircraft hit? Why had the building collapsed so suddenly, defying the laws of science? And why were the authorities seemingly intent on hushing up his story?
Incredible though it seems, Rodriguez decided there could be only one explanation. It was a coverup.
And there could be only one reason for a cover-up - the US government itself was behind the attacks.
The suggestion that the US administration would instigate an attack on its own people, wiping out more than 3,000 lives, may seem wholly implausible - but it's a theory that's gaining considerable ground.
A recent poll by the respected New York Times revealed three out of four Americans now suspect the US government of not telling the truth about 9/11. That proportion has shot up from a year ago, when half the population said they didn't believe the official story.
So what could be the reason for this acceleration?
Well, it's largely down to a 90-minute internet movie called Loose Change, in which Rodriguez appears, made for £1,500 on a cheap laptop by three young American men.
A blitz of statistics, photographs pinched from the web, eye-witness accounts and expert testimony, all set to hip-hop music, it poses the question that's now on everyone's lips - did the Bush administration fabricate an outrage against civilians to fool the world and provide a pretext for war on Al Qaeda and Iraq?
Needless to say, White House sources and US intelligence services have roundly denied and condemned the allegations, but nagging suspicions remain and are now being furiously debated on both sides of the Atlantic.
To add fuel to the fire, a documentary series called The Conspiracy Files, shown last Sunday on BBC2, has also explored the unanswered questions surrounding 9/11.
It seems Rodriguez couldn't have chosen a better time for a nationwide speaking tour of Britain, in which he is setting out his conspiracy theory. But then cynics might argue this is no coincidence.
Next Monday, the people of Sussex will have a chance to make up their own minds about his remarkable story when he pitches up at Sussex Downs College in Lewes for one of 22 speaking dates around the country.
Punters will not be disappointed because he does not short-change his public.
An animated speaker, his words pour forth in a torrent and his story has grown polished in the telling.
But let's go back to the beginning, to Rodriguez's beginnings.
William Rodriguez grew up in Puerto Rico, where he was hired as a magician's assistant by one James Randi, the famous debunker of pseudo-science.
Using the name Roudy, Rodriguez exposed faith healers and psychics and was even featured on TV escaping from a chained straightjacket while hanging from a burning rope.
But after emigrating to New York, he discovered there was a lot of competition in the magic business, and to keep the wolf from the door he took a temporary job at the World Trade Centre.
He ended up staying there for 20 years, little realising how dramatically his employment would be terminated.
Rodriguez will never forget the chaos and hysteria that ensued after the first explosion, which seemed to emanate from the building's very foundations.
"I was talking to my supervisor when I heard boom', very loud, and everybody in the room was pushed upwards," he says.
The impact shook the whole building, and everyone in the office - about 15 in all - started screaming.
There was worse to come. Suddenly a man came running into the room, shouting, "Explosion!
The man was Felipe David, whose job, Rodriguez later discovered, was to replenish the vending machines. He had been standing in front of a lift about 400 yards from the office when a fireball had burst out of the lift shaft.
"His injuries were terrible," says Rodriguez. "All the skin had been burnt off his arms and it was hanging loosely like a flapping shirt sleeve. Parts of his face were missing, too.
"Now you tell me how an explosion from a jet liner could have burnt a man 90 floors down within seconds of impact?"
Lifting the man onto his shoulder, Rodriguez began to make his way to the exit, urging his fellow workers to follow him. But after taking David to a waiting ambulance, he then ignored the shouts of police officers and raced back to the building.
He didn't have far to look to find people in trouble - this time, two victims trapped between two levels in a lift which was rapidly filling with water.
The water was already round their waists and he thought he had no hope of reaching them. But then a silent prayer was answered when he suddenly remembered that ladders were kept in a nearby store cupboard.
Grabbing the longest of the three (by some miracle, it was not chained to the wall like the others), he prized open the lift doors with the help of another man and rescued the two trapped people from a certain watery grave. Then he carried them outside to safety and returned once again to the building.
By this time, firefighters had arrived at the scene.
Rodriguez quickly led them up the stairwell of the North Tower, unlocking doors with a master key, one of only five that opened every door in the building.
And then a series of strange things happened which remain unexplained to this day.
As they ascended the stairwell, they heard a series of massive explosions between the 20th and 30th floors. Then, on the 33rd floor, they heard what sounded like heavy equipment being dragged across the level above.
This was particularly puzzling because Rodriguez knew the 34th floor was empty and had been off limits for weeks due to a construction project.
But on they went, until, at the 39th floor, Rodriguez was ordered to turn back by the firefighters.
It was as he began his descent that he heard the second aircraft hit the South Tower.
Reaching ground level, he was confronted by what looked like a war zone.
The metal-framed front doors to the building had been blown out, leaving a gaping chasm, and the bottoms of the lift doors had been blown open, suggesting a powerful explosion from the basement.
Then the unthinkable happened. Someone yelled, "Don't look back," and he realised the building was coming down.
Frantically looking for cover, Rodriguez raced to the first thing he saw - a fire engine standing only metres away.
"I slid right under the vehicle and then the building collapsed on top of me," he says. "I felt sure I was going to die."
But, of course, he didn't. Instead, remembering the survival training drummed into him as a magician's apprentice, he slowed his breathing and tried to relax as much as possible.
"The only think I could think about was my mother. I didn't want her to have the pain of identifying my mangled body parts. I kept thinking: Oh God, I will never be recognised and my mother won't know who I am.' "
He had reason to worry. As he had raced to the fire truck, he had seen the bodies of what became known as the "jumpers" - the poor souls who had jumped from the building to escape an even worse death inside.
"Their bodies had deteriorated on impact and all you could see were body masses," he says.
Thankfully, for the second time that day his prayer was answered. Two film crews had spotted him running for cover moments before the collapse, and directed rescue services to the very spot where he lay.
Four-and-a-half hours later, he was breathing fresh air again and searching for victims. There wasn't a scratch on his body.
Overnight, Rodriguez was feted as a hero and became a symbol of 9/11.
He was interviewed on countless TV stations and later received a National Hero Award from the Senate of Puerto Rico.
As the months wore on, he became an activist, fighting for tax relief for victims of terrorism, and scholarship programmes for children who had lost their parents on 9/11.
He also helped to set up family support groups and worked on a financial repair programme for victims of September 11.
It wasn't long before the Republicans recognised the power of his appeal, not least to the all important Hispanic community which held 30 million votes in its sway. They asked him to run for office, sending him to train at the Governing Institute to learn about politics.
But all the while questions were nagging away at the back of his mind.
What had caused the explosion that he and countless others had heard in the basement? And why had the Twin Towers fallen so quickly - "like a controlled demolition", as Rodriguez describes it?
The official version was that they had collapsed because their steel columns had melted in the heat from the fuel fires of the two crashed aircraft.
But the science didn't stand up. Steel doesn't melt until it reaches 2,800 degrees Fahrenheit, and open fires of jet fuel - such as those in the Twin Towers inferno - can't rise above 1,700 degrees.
Could it be explosions in the basement helped the Twin Towers on their way?
The makers of Loose Change certainly seem to think so, and show clip after clip of the towers coming down to loud and distinct bangs.
But there were other unanswered questions.
Why were no military aircraft scrambled in time to head off the attacks and why did the President, sitting in a school classroom, show little reaction when an aide told him a second aircraft had crashed into the Twin Towers?
Had he known about it all along?
These were just some of the questions Americans wanted answered, and Rodriguez was among the many who demanded a formal investigation - which ultimately became the 9/11 Commission.
But the Bush administration resisted, arguing they didn't need an inquiry because they already knew who had done it. And that, says Rodriguez, was an affront to every victim of 9/11 and to all their families.
"That's when we knew they were politicising the tragedy."
Rodriguez was one of the last to testify to the Commission and the only witness to speak behind closed doors.
When I ask why, he laughs and says: "Thank you.
I have been asking the same question. Every other testimony was shown on TV. Everyone else had a public hearing."
The interview process was a travesty, he says. They didn't call one of his 20 expert witnesses and his account was edited out of the Commission's report.
"My allegations were never investigated and the perpetrators never caught. The people they did question - the chiefs of the fire and police departments - weren't even in the building. It was a complete whitewash."
In desperation, Rodriguez turned to the National Institute of Standards and Technology (NIST), which was investigating the collapse of the World Trade Centre, promulgating his theory about the explosion in the basement.
He alleges his claims were rebuffed.
NIST said the explosion might have been caused by a fireball travelling from the aircraft down the central lift shaft. In that case, replied Rodriguez, why were the two people he rescued from the lift not burnt to death?
He also turned to the FBI, but they were wholly uninterested in what he had to say, even when he reported he'd seen a mystery man - "possibly one of the hijackers, although we don't know whether he was attached to the government" - asking questions about the layout of the complex just a few months before the attack.
Dissatisfied, he filed a civil lawsuit against the Bush administration in 2004, claiming a conspiracy.
The government filed a motion in turn, dismissing the case on the grounds of national security.
Rodriguez and his team then responded by filing an affidavit alleging the defendants "had knowledge that the attacks were impending but failed to take countermeasures because they desired such attacks to occur".
In 2005, his attorney also proposed a 9/11 petition to the UN, calling for a resolution of the UN General Assembly for an independent September 11 truth commission.
Needless to say, this has made Rodriguez many enemies and he alleges his apartment has been broken into and his laptop stolen. He has also been placed on the no-fly list.
He laughs. "I'm a national hero but I'm on the no-fly list, which means every time I want to fly, the authorities put me in a room and ask me questions.
"Do I fear for my life? Of course. Several experts in the intelligence and security fields have told me to be careful, and say an attack could come from anywhere at any time."
But he won't give up. He has received a "positive"
response from the British people, who are angry that British soldiers' lives have been lost on the strength of a "fallacy". And he knows support for his cause is growing.
He's even thinking of running as an independent political candidate. But in the meantime, he has something more tangible to lift the gloom. He is going to be a father.
"I married a year ago - to an American reporter, as a matter of fact. And my wife's doctor broke the news.
"He said, Congratulations. You're expecting. And the due date is September 11.' "When I started crying, he said: Oh, it's your first baby.' But my wife said: No, you don't understand. This is the janitor from the World Trade Centre.' And then the doctor started crying, too.
"Now, isn't that incredible?"
- William Rodriguez will be speaking at Sussex Downs College in Mountfield Road, Lewes, at 7.45pm on Monday.
Admission, priced £5, is on the door only.
The talk is being organised by the Lewes-based Changing Times organisation, which aims to raise awareness of important political and social issues. For further information, visit www.changing times.org.uk
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