Extract from the SFO's reply:

The 30 November letter also invoked section 31 (law enforcement) and again concluded that the public interest favoured withholding the information. In my judgement this too was correct. There is, as you have noted elsewhere, considerable material in the public domain about the collapse of Equitable Life, but releasing what SF0 holds which is not in the public domain would prejudice our ability to conduct effective investigations, and where appropriate prosecutions, in the future.

The SFO's reply seeks to assure Stephen that in denying him the information he seeks under the FoI act, it simply has the public's best interests at heart. But why should anyone believe this?

The letter is a tacit admission that the SFO indeed holds additional material to that in the public domain but we are invited to believe that the reason it is still being withheld is because it might prejudice future investigations and a possible prosecution. We can only speculate what that additional material (and documented exchanges with outside bodies?) may be, but ten years of inaction later, this lame excuse beggars belief. Surely the SFO's response demonstrates not the lack of evidence to prosecute or investigate but the lack of will. Why would that be and who would be pulling the strings?

FoI Exemption - Section 31:

www.justice.gov.uk/about/docs/foi-exemption-s31.pdf

Extracts

Section 31 is concerned with protecting a wide range of law enforcement interests and its application turns on whether disclosure would be likely to prejudice those interests....

The exemption in section 31(1)(a) is designed to cover all aspects of the prevention and detection of crime. Section 31(1)(b) is intended to cover all stages of the apprehension process and the subsequent prosecution of criminal activity, including, for example, making or preparing to make an arrest or an application for an arrest warrant, and all stages of prosecution, including for example making or preparing to make an application for a summons (or 'written charge and requisition')...

If it is clear that prejudice would, or would be likely to, arise, the balance of the public interest in disclosing and withholding the information must be considered. In common with other prejudice-based exemptions, the nature, degree and likelihood of the prejudice to be caused will need to be taken into account in considering the balance of public interest in disclosure (see part 3.3 for general guidance on the application of the public interest test)...