Lord Justice Irwin gives the leading judgment in UB (Sri Lanka) v Secretary of State for the Home Department  EWCA Civ 85, in which the Home Office failed to serve a relevant policy document during an appeal:
16. In my view there was the clearest obligation on the Secretary of State to serve relevant material and ensure it was before the Tribunals at both levels. In AA (Afghanistan) v SSHD  EWCA Civ 12, Keene LJ made the point clear beyond doubt:
“27. [It was submitted by the appellant that] the attention of the adjudicator should have been drawn by the Secretary of State’s representative to the policy on interviewing unaccompanied minors, so as to avoid him being misled: see R v. Special Adjudicator, ex parte Kerrouche  Imm AR 610.
28. As a matter of law, that is right. The Secretary of State should draw relevant parts of his policy to the adjudicator’s attention. Merely because those policy documents are publicly available in print or on a website is not enough: where issues of risk of persecution are involved, a decision to return a person or not to his country of origin should not depend on the diligence of that person’s representatives.”
17. The point was reinforced by Lord Wilson in Mandalia v SSHD  1 WLR 4546  UKSC 59. Lord Wilson referred to the judgment of Keene LJ in AA (Afghanistan) and re-emphasised the obligation:
“irrespective of whether the specialist judge might reasonably be expected himself to have been aware of it, the Home Office presenting officer clearly failed to discharge his duty to draw it to the tribunal’s attention as policy of the agency which was at least arguably relevant to Mr Mandalia’s appeal.” (paragraph 19)
21. I deprecate any suggestion that this obligation of service is displaced or diminished by the availability of the material online. Mr Hare for the Secretary of State did not in fact mount this argument, although it seems likely from exchanges before the hearing that he was pressed to do so. He was right to decline such an argument. Apart from the clear obligation in law derived from authority, many appellants in immigration and asylum cases are unrepresented. In a number of cases where there is legal representation, the quality of representation is less than optimal.
22. The obligation is clear but must not be taken beyond the proper bounds. There is no obligation on the Secretary of State to serve policy or guidance which is not in truth relevant to the issues in hand, and complaints as to alleged failures of disclosure of material which is truly peripheral or irrelevant should readily be rejected.