Theresa May faces questions over her role in the parts which were redacted from the American Senate's damning report on torture techniques used by the CIA after 9/11.
MPs on the influential Home Affairs Select Committee want to know whether she asked for sections to be redacted because they could embarrass Westminster.
The parliamentary panel investigating allegations of British involvement in torture following 9/11 has asked to see secret material from a damning CIA report.
Intelligence and Security Committee (ISC) chair Sir Malcolm Rifkind requested any redacted sections relating to the UK's role in the interrogation of terror suspects.
Sir Malcolm said it was for the US Government to decide whether to supply the material.
Asked if he was hopeful of success, he said: "I do not say I would be confident."
Downing Street has confirmed British spies spoke to their US counterparts to discuss blacking out some sections.
But it insisted it related only to "national security grounds" and was not to cover-up British complicity in torture.
A former US Vice President has condemned a shocking report into interrogation techniques used by the CIA, slamming it as "full of crap".
While it seems beyond the realms of possibility now, things can change, what is unlikely now is conceivable in 30 years time.
Shocking details about the CIA's "brutal" interrogation techniques have been laid bare. (Note: graphic descriptions may cause upset)