It is no matter of Euclidian geometry to say that where x + y = z, and z = 13, being told what y equals one need not be Pythagoras to establish the value of x. But what happens when z is in the public domain, x is absolutely exempt information under FOIA (because it is caught by section 23(1)) and the public interest otherwise favours the disclosure of y, which is not the subject of an exemption? Inevitably, the effect of disclosure is that the absolutely exempt information is also revealed. The Interim Decision of the Upper Tribunal in Home Office v ICO & Cobain  UKUT 306 (AAC) was that the Tribunal had to consider whether it was appropriate to utilise the section 50(4) FOIA power so as not to direct disclosure. The issue may be formulaic, but the answer is not.
The application of section 50(4) has only previously received analysis in ICO v HMRC & Gaskell  UKUT 296 (AAC), in which Judge Wikeley held (at ) that section 50(4) could be used so as not to require disclosure of information where it would be “unlawful, impossible or wholly impractical”. On the facts of Gaskell, section 50(4) was appropriate because since the request had been made the law had made disclosure of the information unlawful.
The Upper Tribunal has now exercised that decision itself in Home Office v ICO & Cobain  UKUT 27 (AAC), in which Judge Wikeley held that the appropriate exercise of the section 50(4) discretion requires no steps to be taken (i.e. y need not be disclosed, even though section 1 FOIA entitles Mr Cobain to see it). The Upper Tribunal stressed that the application of section 50(4) should be rare, given the need to construe FOIA liberally, and use of it must be lawful in a public law sense. Judge Wikeley broadly endorsed the ICO’s ten listed factors as of potential relevance (although they will vary on the facts of each case): at . He saw it as particularly important that the absolute exemption which would be undermined in this case was section 23(1), expressly drawn widely by Parliament and by contrast to section 24. Indeed, he accepted that section 23 “affords the widest protection”: at . Judge Wikeley also considered the degree of public interest in the information, which he considered not to be especially high given the existing material in the public domain. He therefore agreed that section 50(4) should be applied so as not to require the Home Office to take steps to disclose the information.
It remains to be seen how often there really will be such issues in practice. The Cobain case appears to be the first of its type, although the Upper Tribunal recognised that it might occur under other class-based exemptions, such as sections 30, 35, 41 and 42. What may be more interesting is where different exemptions apply to x and y, one of which is absolutely exempt and one of which is subject to a qualified exemption. Is the algebraic problem a matter for the public interest balance in relation to y, or should it only be resolved at section 50(4)? Strictly speaking, one can see the analytical purity of considering the interest only in relation the specific information covered by y, but it is hard to imagine that the impact of disclosure in relation to x will not bleed across into the weighing. And if there has already been a public interest exercise, what room will there remain for it to be taken into account under section 50(4) – in such cases it would look a lot like double-counting. Perhaps we shall never know, and this may be what happens when the maths fox runs loose in the FOIA henhouse.
One brief procedural addition. The Upper Tribunal had, in ICO v Bell  UKUT 106 (AAC), held that the Tribunal should usually explain that a Decision Notice was wrong in law and why, rather than substituting a new Decision Notice. Judge Wikeley was rather less convinced at the appropriateness or necessity of that conclusion (see at -, and in particular the amusing and obvious implicit support given to the Tribunal’s castigation of Bell in Clucas v ICO (EA/2014/0006)) and happily availed himself of the crack left open by Judge Jacobs in Bell to substitute a new Decision Notice in this case. Given that it was a case using section 50(4), that seems a particularly sensible step. Doubtless a case will arise in which Bell can be reconsidered, and God bless all those who have to sail in her.
In the meantime, it is time for FOIA lawyers to get back to the calculators.