The Detainee Inquiry, headed by Rt. Hon. Sir Peter Gibson, was supposed to have investigated the allegations of complicity in torture and "extraordinary rendition", by the British government, especially its secret intelligence agencies - MI5 Security Service, SIS Secret Intelligence Service, GCHQ and possibly DIS the Defence Intelligence Staff.
However the Detainee Inquiry has been shut down before it even got started formally, even after 18 months delay, supposedly because of the suspiciously lengthy and ineffective Metropolitan Police Service and Crown Prosecution Service investigations into old allegations and the effect of the "smoking gun" documentary evidence discovered in Libya last autumn.
In order to probe exactly how potential witnesses and whistleblowers to the Detainee Inquiry might be protected from vengeful secret bureaucrats, Spy Blog requested, under the Freedom of Information Act 2000, the full, detailed text of the latest draft(s) (or the final version) of the promised undertakings from the Attorney General and the Cabinet Secretary and the heads of the intelligence services.
These Undertakings were promised by Prime Minister David Cameron when he set up the Detainee Inquiry over 18 months ago: The Prime Minister's Letter to Sir Peter Gibson 06 July 2010 (.pdf)
See the Spy Blog - FOIA request blog for the text of these FOIA disclosures:
Attorney General's Office disclosure
This seems to be a reasonable level of legal immunity, especially for criminal offences which the Attorney General himself decides whether to prosecute or not e.g. Official Secrets Act cases.
The Detainee Inquiry is not a Tribunal or Court of Law (despite being chaired by a retired senior Judge) and it was not set up as an inquiry under the Inquiries Act 2005 and so it has no legal power to compel any witnesses to give evidence,
How can it can enforce any prosecutions for giving, or conspiring to give it any "false evidence", which the Attorney General's undertaking explicitly does not give immunity for ?
Cabinet Office disclosure
As expected by Spy Blog, the Cabinet Office letter by the then Cabinet Secretary Sir Gus O'Donnell (now Lord O'Donnell of Clapham) and its "overarching principles" seem suitable for protecting witnesses who are current or former intelligence agency staff members who espouse the official line e.g. by treating evidence given within the Terms of Reference of the Detainee Inquiry, as having been given "lawful authority" for the purposes of the Official Secrets Act 1989 section 7 Authorised disclosures
However the letter does not really provide the necessary guarantees for any whistleblowers who might contradict their current or former bosses.
Neither is it clear what whistleblower guarantees the vast array of private military contractors, defence industry suppliers and sub-contractors etc. who are not civil servants, but who will fear that their security clearances and government contracts could be at risk if they make allegations, or provide evidence which contradicts the official intelligence agency briefing positions, which those agencies might have provided to the Detainee Inquiry or which they might do so to a future inquiry.
There is no explicit prohibition on using the self authorised legal powers, human and technological resources available to each intelligence agency, to prevent them from snooping on the members and staff of the Detainee Inquiry itself (and their friends and families), so as to try to obtain advance notice of the identities of potential whistleblowers and the information or evidence which they might be offering to the Detainee Inquiry.
Spy Blog correspondence with the Detainee Inquiry