The chair of parliament's intelligence and security committee has urged Shaker Aamer to submit evidence to its behind-closed-doors inquiry into alleged UK complicity in torture.
Mr Aamer, the last Briton to be released from Guantanamo Bay, has demanded a full public inquiry into the actions of the security services.
In his first TV interview, Mr Aamer told ITV News that British intelligence officers were complicit in his detention and torture.
Former attorney general Dominic Grieve told ITV News the allegations "have to be taken very seriously and we will do so" as he called on Mr Aamer to cooperate with his inquiry.
"It is very much in our interests to look at and find out what happened," he added.
Asked whether former prime minister Tony Blair and former foreign secretary Jack Straw would be called to give evidence, Mr Grieve said: "The committee will decide as it goes along who it calls. I rule nobody in and rule nobody out."
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