When a well-known BBC sports television presenter and spokesperson for the Green party appears on a chat show, it is fair to say you would not expect too much controversy from the interview. You wouldn't for example expect him to claim he was the Son of God.

But when former Coventry City goalkeeper David Icke appeared on Terry Wogan's primetime chat show on April 29, 1991, that is exactly what happened.

"2000 years ago had a guy called Jesus sat here and said the same thing, you'd still be laughing, it's really funny that we've not really been moved on that much," was his justification for the claim.

His further predictions that world was set to be destroyed by tidal waves and earthquakes, effectively destroyed any credibility he previously had.

20 years on, Icke is still expressing mad-cap theories about how all of humanity is controlled by a secret group of shape-shifting reptilian humanoids called the Babylonian Brotherhood and our world leaders, such as Barack Obama, George Bush Snr and Queen Elizabeth II, are the result of reptilian cross-breeding.

Shapeshifting George Bush?
Proof of George Bush transforming into a reptile, according to one of Icke’s videos.

Except now he is expressing his views in lectures to thousands of people in more than 25 countries.

"We are not alone. The idea that humans are the only two-legged, two arms intelligent lifeform is ridiculous. These reptilian entities exist and they are influencing our world from beyond human sight...interbreeding between human and non-humans has created a new form...this hybrid race are the Royal Family, the politicians, those running the banking system, the media."

This is just a selection of theories, ideas and ramblings that Icke presented to a sell-out crowd at the 2,100 capacity venue in New York City's Best Buy Theatre during a mammoth eight hour talk as he continues his surprise prolonged career as a public speaker and writer setting out to reveal "the truth."

His latest tour comes off the back of the release of his 18th book called Human Race Get Off Your Knees. In his latest literary ramblings, Icke writes how the moon is in fact a spacecraft controlled by reptiles and a fake reality broadcast from the Moon, called the 'Moon Matrix', is decoded by the human mind the same way as portrayed in the Matrix movie trilogy. The Moon Matrix has 'hacked' into the human 'body-computer' system, and it is feeding us a manipulated sense of self and the world 24/7.

As well as the more bizarre theories of reptiles controlling the world and the moon being a hollow spacecraft in his books, he has also touched on the more common conspiracy theories, such as Princess Diana was assassinated by the Royal Family, presumably because she was not a half-human/ half-reptile hybrid like the rest of them, and that 9/11 was an inside job.

He is due to release another next year book, followed by yet another world tour, with tickets costing as much as £45. He is even due to appear at the Wembley Arena in 2012.

His website describes this year as his "20th year of uncovering astounding secrets and suppressed information." Despite his ideas being ones that are easily laughed away, Icke has still managed to attract a huge army of fans who take his word as gospel. Robbie Williams is believed to have taken an interest in his work and Muse frontman Matt Bellamy thinks that there may be something in the idea that our world leaders have reptilian blood inside tem.

Whatever you think of Icke and the subject he writes and speaks about, you can't help but be admired how he has been able to make a lucrative business by suggesting completely unproven ideas as "fact," when most people would be sectioned for doing so.

"They're laughing at you, not with you," quipped Wogan on his chats how in 1991. It isn't hard to imagine that it is Icke who is having the last laugh after 20 years.