If you have ever wondered why Americans are obsessed with conspiracy theories it's due to their culture dating back hundreds of years.

America was founded on conspiracies being hatched by politicians in London to take away liberties of people, according to Britain's leading conspiracy theory expert.

Professor Sir Richard Evans of the University of Cambridge, who is leading a research project due to be published in 2017, told the Hay Festival: "Conspiracy theories are very widespread in the United States. It seems to me that they are more widespread than in other countries.

"There is an argument that conspiracy theories are built into American culture because that is how America started. The United States was founded on conspiracy theories that the London government was conspiring to deprive America of their liberties."

His research also goes contrary to belief that the internet is the main cause for the proliferation of conspiracy theories.

He cites an array of conspiracy theories in the United States including John F Kennedy's assassination in 1963. According to a 2013 Gallup poll, a clear majority of Americans (61%) believe others besides Lee Harvey Oswald were involved. This percentage, however, has now been reduced since the rise of the internet.

"There is now a lot more scepticism," Evan said.

Other theories include the 9/11 attacks and campaigns to prove that President Obama was not American. He said that opinion polls recorded 28% of Republicans believed the President was the Antichrist, along with 6% of Democrats.

Conspiracies, he said, tended to proliferate after traumatic incidents, such as the disappearance of missing MH370 this year. The McCarthy "witch-hunts" against communist sympathisers followed the end of the Second World War and had taken on "a life of their own" were another example.

He also pointed out that while in earlier financial crises, conspiracy theories were directed at big business, during the recent crisis, anger and theories had been aimed at governments.

"In the late 19<sup>th century conspiracy theories were directed against big business and cartels", he said.

"This did not happen so much in the recent economic crisis where conspiracy theories have been targeted much more at government. Is it because governments play a much bigger role in our lives than they did a century ago?"