WikiLeaks founder Julian Assange refused to meet actor Benedict Cumberbatch who plays him in a new film because he believed it would only help destroy his organisation.
Assange, 42, who has been holed up in the Ecuadorian Embassy in London for more than a year to avoid extradition to the United States - refused the request to meet as Cumberbatch prepared for his role in The Fifth Estate.
Despite Assange railing against the film, two days before it hits cinema screens he has released a letter he wrote to the actor on his website.
Assange claims the Dreamworks production is based on a "toxic" book and believes the film "will distort events and subtract from public understanding" of his work.
Cumberbatch, 37, star of BBC hit Sherlock, plays the platinum-haired Australian in the film and he wrote to him requesting a meeting.
The actor wanted a chance to study Assange's mannerisms.
Assange told him: " I think I would enjoy meeting you.
"The bond that develops between an actor and a living subject is significant. If the film reaches distribution we will forever be correlated in the public imagination.
"Our paths will be forever entwined. Each of us will be granted standing to comment on the other for many years to come and others will compare our characters and trajectories.
"But I must speak directly.
"I hope that you will take such directness as a mark of respect, and not as an unkindness.
"I believe you are a good person, but I do not believe that this film is a good film.
"I do not believe it is going to be positive for me or the people I care about.
"I believe that it is going to be overwhelmingly negative for me and the people I care about.
"It is based on a deceitful book by someone who has a vendetta against me and my organisation.
"In other circumstances this vendetta may have gone away, but our conflict with the United States government and the establishment press has created a patronage and commissioning market - powerful, if unpopular - for works and comments that are harmful to us.
"There are dozens of positive books about WikiLeaks, but Dreamworks decided to base its script only on the most toxic.
"So toxic is the first book selected by Dreamworks that it is distributed to US military bases as a mechanism to discourage military personnel from communicating with us. Its author is publicly known to be involved in the Dreamworks production in an ongoing capacity."
Assange said the US Government has him and WikiLeaks in its crosshairs and "f eature films are the most powerful and insidious shapers of public perception".
"This film is going to bury good people doing good work, at exactly the time that the state is coming down on their heads," Assange wrote.
The father-of-one said the film "will claim to be fiction" but is " distorted truth about living people doing battle with titanic opponents".
He added: "It is a work of political opportunism, influence, revenge and, above all, cowardice.
"It seeks to ride on the back of our work, our reputation and our struggles.
"It seeks to cut our strength with weakness. To cut affection with exploitation. To cut diligence with paranoia. To cut loyalty with naivety. To cut principle with hypocrisy. And above all, to cut the truth with lies."
And the activist warned Cumberbatch: " You will be used, as a hired gun, to assume the appearance of the truth in order to assassinate it. To present me as someone morally compromised and to place me in a falsified history. To create a work, not of fiction, but of debased truth.
"Not because you want to, of course you don't, but because, in the end, you are a jobbing actor who gets paid to follow the script, no matter how debauched.
"Your skills play into the hands of people who are out to remove me and WikiLeaks from the world."
Assange signed off "with inexpressible regret", that he had to turn down Cumberbatch's request.