Former FBI agent Ali Soufan has denied claims that waterboarding produced important intelligence results, saying he believes President Bush was not told the truth when he claimed it had saved lives.
He told HARDtalk's Tim Franks that 9/11 suspect Khalid Sheikh Mohammed continued to mislead interrogators despite being waterboarded more than 180 times.
Soufan was at the heart of the US battle against al-Qaeda until he left the FBI in 2005 and came out publicly against torturing suspected terrorists to extract information.
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You can watch the full interview on Wednesday 19 October on BBC World News at 03:30 GMT, 08:30 GMT, 15:30 GMT and 20:30 GMT.
And on BBC News Channel on Wednesday 19 October at 04.30 and on Friday 21 October at 00:30 and 04.30 BST.
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