Jeremy Corbyn has claimed that 9/11 was “manipulated” to make it look like Osama Bin Laden was responsible to allow the West to go to war in Afghanistan.
In comments that will raise questions about his suitability to lead the Labour Party, Mr Corbyn appeared to blame George Bush and Tony Blair for using the September 11 attacks in New York to allow them to go to war.
In a series of further articles, Mr Corbyn also appears to endorse controversial conspiracy theories about a “New World Order”.
It comes as Mr Corbyn prepares for his first conference as Labour leader.
Mr Corbyn will attempt to use the Brighton conference to unite the party after it threatened to split apart in the wake of his shock election victory.
However, a number of Labour MPs are expected to use the conference to publicly state that the party is unelectable under Mr Corbyn.
Lord Mandelson on Friday said that the party should only consider ousting Mr Corbyn after it is clear the public have realised the party “cannot be elected with Corbyn as leader”.
Mr Corbyn was heavily criticised in the days before winning the Labour leadership after suggesting that the death of Osama Bin Laden was a “tragedy”.
In the 2003 article for The Morning Star newspaper, Mr Corbyn wrote: “Historians will study with interest the news manipulation of the past 18 months.
“After September 11, the claims that bin Laden and al-Qaida had committed the atrocity were quickly and loudly made.
“This was turned into an attack on the Taliban and then, subtly, into regime change in Afghanistan.”
However, in previous years he wrote a series of articles which appear to have endorsed the conspiracy theory about the “New World Order”.
The “New World Order” conspiracy is frequently linked to theories about the so-called “Illuminati” and claims about a “totalitarian world government”.
In an article for “Labour Briefing” in 1991, Mr Corbyn wrote: “We now know that the Gulf War was a curtain-raiser for the New World Order: the rich and powerful, white and western will be able to maintain the present economic order with free use of all the weapons they wish for.”
That same year, he said in Socialist Campaign Group News: “The aim of the war machine of the United States is to maintain a world order dominated by the banks and multinational companies of Europe and North America.”
The following year, in a piece for Labour Peace Action, Mr Corbyn said: “What is required now is a bold, democratic alternative to the New World Order. The US veto at the Earth summit in Rio…shows just who calls the shots in this New World Order and who will be asked to foot the bill.”
Mr Corbyn has previously shared a platform with Ken O’Keefe, who has alleged that President Bush was a member of The New World Order who had orchestrated the September 11 attacks for personal gain.
The phrase was also used in a speech by George H.W Bush. Mr Corbyn’s spokesman refused to deny that the new Labour leader was referring to the “New World Order” conspiracy theory in his articles.
Labour on Friday said that Mr Corbyn will use the conference to focus on the economy, foreign policy issues and “participative politics”.
However, in a sign of the divisions in the party, Labour admitted that “differences of opinion” will emerge during the conference.
n a briefing note, the party said: “There is widespread agreement that [Mr Corbyn’s conference themes] are the pillars of the huge mandate provided by the leadership election. Differences of opinion will emerge within these parameters, but this provides the framework for change established through Jeremy Corbyn’s mandate.”
Mr Corbyn on Friday confirmed that he will work with the SNP to try and scrap Britain’s nuclear deterrent despite opposition to the move from his own backbenches.
The Labour leader reaffirmed his long-standing opposition to Trident and said he would vote with the 56 Nationalists at Westminster on the issue.
Left-wing activists will debate scrapping Trident at next week’s conference.