Shaker Aamer has told ITV News he is "scared" the UK security services may "do anything" to silence him since his release from Guantanamo Bay.
Mr Aamer, the UK's last detainee at the prison camp, told Julie Etchingham he felt less secure for "telling the world what happened" to him.
"I really don't want to upset anybody and don't want to start anything in this country that can jeopardise their security," he said.
"But at the same time all I'm doing is telling the truth, that's all."
Tony Blair and George Bush should be given immunity from prosecution in order for the world to learn the truth about claims the US and British were complicit in torture at Guantanamo Bay, Shaker Aamer has told ITV News.
"Accusing governments, accusing individuals is not going to give us the chance to know the truth," he told Julie Etchingham in his first TV interview since being released from the notorious prison camp.
The UK's last Guantanamo detainee said he believed the former British prime minister and US president are both "scared" of being jailed, adding: "How can you expect fear is going to bring justice and bring the truth out of these guys?"
Asked whether he expected Mr Blair would reveal more details about Guantanamo, Mr Aamer said: "If he guaranteed that he's not going to be behind bars I think he would. At least he would be more open about it."
Mr Aamer, who has detained for 14 years without charge, said he believed "nobody should be prosecuted because of what happened in the past" in order to prevent it from happening in the future, saying it would not lead to justice.
A spokeswoman for Mr Blair has said he "never condoned" the use of torture.
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A Saudi national and British resident, detained at Guantanamo for 14 years without charge - here's what you need to know about Shaker Aamer.Read the full story ›
Beaten, hog-tied and deprived of prayer - former Guantanamo detainee Shaker Aamer tells ITV News what he says life was like inside the camp.Read the full story ›
Shaker Aamer gave his first TV interview to ITV News after being released from Guantanamo, following 14 years in detention without charge.Read the full story ›
Five detainees at the Guantanamo Bay facility on Cuba have been transferred to the government of the United Arab Emirates, the Pentagon has announced.
Shaker Aamer, the last British detainee at Guantanamo Bay, arrived back in the UK on Friday afternoon.Read the full story ›