In the seven years since he founded WikiLeaks, Julian Assange's relationships with a number of his former collaborators and supporters have broken down, with each side variously claiming broken promises or bad faith on the part of the other.

On Wednesday Jemima Khan, a former close supporter of Assange's who stood bail for him while he fought extradition to Sweden over sexual assault accusations, became the latest to speak of becoming "alienated" from the Australian after she executive-produced a film he believes to be "anti-WikiLeaks".

Khan, who is associate editor of the New Statesman, has written an article for the magazine about losing faith in Assange, saying she has come to believe that he is "undermining both himself and his own transparency agenda – as well as doing the US department of justice a favour – by making his refusal to answer questions in Sweden into a human rights issue". She suggests he risks becoming like "an Australian L Ron Hubbard", in a reference to the founder of Scientology.

Assange is confined to the Ecuadorian embassy in London, where he sought asylum last June after losing his legal attempts to avoid extradition to Sweden, where he is wanted to answer allegations of rape and sexual assault against two women.

Assange denies the claims, and argues that he fears that if he was remanded in Sweden he would be at greater risk of onward extradition to the US to face potential prosecution for espionage relating to the WikiLeaks cable releases.

The core of her disaffection, Khan argues, is her view that "WikiLeaks – whose mission statement was 'to produce ... a more just society ... based upon truth' – has been guilty of the same obfuscation and misinformation as those it sought to expose, while its supporters are expected to follow, unquestioningly, in blinkered, cultish devotion".

She says that when she told Assange she was involved in the film We Steal Secrets, directed by the American documentary maker Alex Gibney, she "suggested that he view it not in terms of being pro- or anti-him, but rather as a film that would be fair and would represent the truth ... He replied: 'If it's a fair film, it will be pro-Julian Assange.' Beware the celebrity who refers to himself in the third person".

WikiLeaks has objected to the film's title, saying it is "an unethical and biased title in the context of pending criminal trials. It is the prosecution's claim, and it is false."

The organisation did not immediately respond to a request for comment on Khan's article, but Assange has repeatedly disputed the accounts of those with whom he has fallen out, including his former collaborator Daniel Domscheit-Berg, his former legal team, and journalists from this newspaper and others.

Khan writes that she still believes there are "troubling aspects" to the Swedish sexual assault case, and that "questions may need to be asked" about the Swedish police investigation: "I don't regret putting up bail money for Assange," she says. However, Khan adds: "I did it so that he would be released while awaiting trial, not so that he could avoid answering to the allegations."

She writes of her regret that many of the discussions about WikiLeaks have been more about "tribalism than truth", but she argues: "It would be a tragedy if a man who has done so much good were to end up tolerating only disciples and unwavering devotion, more like an Australian L Ron Hubbard."