In Smart v Director of Personnel Administration (2019) UKPC 35 one issue was whether a decision challenged by judicial review was tainted by the existence of undisclosed documents. There seems to have been “an unfortunate lack of transparency” about an appointment process.   It also seemed unfortunate that the response to a Freedom of Information request was delayed. There was a lack of candour” in not disclosing correspondence.  Lord Carnwath referred, at paragraph 32, to the so-called “presumption of regularity” on the one hand and on the other hand the “well established duty” on a public authority to respond to a judicial review application with “all the cards face upwards on the table”.  The Privy Council, at paragraph 34, endorsed as the correct approach the following statement (emphasis added):-

“It is in this context of cooperation, where a court has granted leave to pursue judicial review and where the full and candid disclosure of the claimant’s evidence as well as the full, frank and uninhibited explanation – with all primary documents relevant to the challenge (subject only to lawful exemptions) of the public authority are before the court, that the process of evaluation contemplated by judicial review is to be undertaken. … the presumption of regularity ought not to operate as a shield behind which a public authority can hide by refusing to give evidence on the basis that it is for a claimant to prove his case. This is an erroneous and misplaced view of how the presumption of regularity ought to operate in public law matters. Indeed, a presumption of bona fides ought to willingly lead to full disclosure of all relevant information at the earliest opportunity – including in response to pre-action enquiries.”