“In my view, this is … a classic case of mistake. It is quite clear that the present appellant was wholly ignorant of his former wife’s condition and, had he known of it, he obviously would not have consented to the adoption. That ignorance vitiates his consent and means that it was of no effect. In the absence of that consent it is very doubtful whether the adoption order would have been made. Since it is clearly in the best interests of the children that the adoption order should be set aside, I would extend the time for both these appeals … and allow both appeals. I should say, as a postscript, that this is, if not unique, at the very least a wholly exceptional case. I say that because I do not want the setting aside of this adoption order in these circumstances to be thought of as being some kind of precedent for any related set of facts in some other case.”