Many thanks for your comment. We are in fact entirely in agreement – of course it is possible for domestic courts to have curial deference doctrines vis-a-vis their executive branches or administrative agencies or what have you. It is even possible, as you say, for them to call this doctrine the ‘margin of appreciation.’ My point – and the Court’s – was that this would still NOT be the ECHR margin of appreciation doctrine, which deals with the Court’s deference to the judgment of member states on a variety of questions. What the UK government did was to try to interject this ECHR doctrine into the relationship between itself and its own courts, and that is what the European Court thought of as improper. It is not up to the European Court to say whether national courts should defer to the executive branch in any given circumstances, certainly not under the ECHR and its own case law. Even if the English courts had used some sort of deference doctrine, it is again not for the European Court to say whether they have applied it properly or not. It is not a fourth instance court for domestic law, and it is domestic law, not the ECHR, which may or may not provide for deference of domestic courts to the executive.

Thank you for a very useful post, although I’d disagree with the conclusion that the margin of appreciation is a deference doctrine that is applicable only between the Court and the member states, not within the member states themselves. In Canada, for example, our highest court has referred to a “margin of appreciation” as applicable within the State itself to refer to the degree of deference to be accorded by a court to the executive and legislative branch. (See, for example, Irwin Toy Ltd. v. Attorney General (Quebec) at http://scc.lexum.umontreal.ca/en/1989/1989rcs1-927/1989rcs1-927.html). Admittedly, this reference to the words “margin of appreciation” may have come from Canadian judges reading ECHR cases and then using the phrase for our non-European circumstances, or it could reflect French law influences, but it also shows that it is possible to have a margin of appreciation doctrine within a state, and not just applicable to an international court vis-a-vis member states. One can also trace the origins of the ECHR margin of appreciation back to a French public law doctrine of national application, albeit some might find the English to be a rough translation of what is conveyed in French. In any event, while there may be a desire to give a different label to the doctrine when used domestically within the UK (degree of deference) as when used at the ECHR (margin of appreciation), and thus perhaps develop different criteria for invoking the doctrine, at base, the concept appears to be the same. What may be worth considering is the principle of subsidiarity as an additional consideration for determining the margin, as this would not have a domestic equivalent.

Best wishes,
Joanna