The interpretation in the U.K. of the key term “habitual residence” in the Hague Abduction Convention and in Article 8 of the European Union's Council Regulation (EC) 2201/2003 ("Brussels IIA") is now fundamentally different from the interpretation of that term by a majority of the federal circuits in the United States.
Until just a few years ago, the courts in the U.K. “spoke the same language” as most U.S. courts when it came to habitual residence but the U.K. courts have more recently followed European authorities, which focus primarily on the objective facts concerning the child and far less on discerning the often competing claims concerning the intentions of the parents.
In a recent English case, EE and ME (Children) (Habitual Residence)  EWHC 3363 (Fam), the judge provided a most useful summary pf the current state of the law. He stated as follows:
5. This case therefore turns on the question of the habitual residence of the children. On that matter, there has been a considerable body of case law in recent years, most importantly the decisions of the CJEU in Proceedings brought by A (Case C-523 – 07)  Fam 42 and Mercredi v Chaffe (Case C-49710 PPU)  Fam 22 and of the Supreme Court in A v A (Children: Habitual Residence)  UKSC 60, Re LC (Children)  UKSC 1 and Re B (A Child)  UKSC 4. From these cases, the principles relevant to the current application can be summarised as follows.
(1) Habitual residence is a question of fact and not a legal concept.
(2) "The essentially factual and individual nature of the inquiry should not be glossed with legal concepts which would produce a different result from that which the factual enquiry would produce" A v A (Children: Habitual Residence), per Baroness Hale of Richmond at para 54 (vii) A gloss is "a purported sub-rule which distorts application of the rule" per Lord Wilson in Re B at para 46.
(3) The test for the determination of habitual residence should be the same under the Hague Child Abduction Convention, Brussels IIA and domestic law: A v A (Children: Habitual Residence), per Baroness Hale of Richmond at para 54 (iv) and (v).
(4) The test adopted by the European Court, which must be applied in cases in this country, is that habitual residence is "the place which reflects some degree of integration by the child in a social and family environment": Proceedings brought by A (decision), A v A (Children: Habitual Residence), per Baroness Hale of Richmond at para 54 (iii).
(5) To that end, in particular the duration, regularity, conditions and reasons for the stay on the territory of a member state and the family's move to that state, the child's nationality, the place and conditions of attendance at school, linguistic knowledge and the family and social relationships of the child in that state must be taken into consideration: Proceedings brought by A.
(6) It must be shown that the child's presence in the Member State in question is not in any way temporary or intermittent but rather of a lasting character: Proceedings brought by A, Mercredi v Chaffe.
(7) "The social and family environment of an infant or young child is shared with those (whether parents or others) on whom he is dependent. Hence it is necessary to assess the integration of that person or persons in the social and family environment of the country concerned" A v A (Children: Habitual Residence), per Baroness Hale of Richmond at para 54 (vi).
(8) "This is a child-centred approach. It is the child's habitual residence which is in question. It is the child's integration which is under consideration. Each child is an individual with his own experiences and his own perceptions. These are not necessarily determined by the decisions of his parents …. The environment of an infant or very young child is (one hopes) a family environment and so determined by reference to the person with whom he lives. But once the child leaves the family environment and goes to school, his social world widens and there are more factors to be taken into account. Furthermore, where parents are separated, there may well be two possible homes in which the children can live and the children will be well aware of this. This may well affect the degree of their integration in a new environment" per Baroness Hale in Re LC para 62.
(9) "The modern concept of a child's habitual residence operates in such a way as to make it highly unlikely, albeit conceivable, that a child will be in … limbo …. The concept operates in the expectation that, when a child gains a new habitual residence, he loses his old one. Simple analogies are best: consider a see-saw. As, probably quite quickly, he puts down those first roots which represent the requisite degree of integration in the environment of the new state, up will probably come the child's roots in that of the old state to the point at which he achieves the requisite de-integration (or, better, disengagement) from it" per Lord Wilson in Re B para 45.
(10) In identifying the point at which habitual residence was lost and gained, the court might find that:
(a) the deeper the child's integration in the old state, probably the less fast his achievement of the requisite degree of integration in the new state;
(b) the greater the amount of adult pre-planning of the move, including pre-arrangements for the child's day-to-day life in the new state, probably the faster his achievement of that requisite degree; and
(c) were all the central members of the child's life in the old state to have moved with him, probably the faster his achievement of it and, conversely, were any of them to have remained behind and thus to represent for him a continuing link with the old state, probably the less fast his achievement of it."
These "suggestions", made by Lord Wilson in Re B at para 46, are not intended to be glosses or sub-rules but, rather, expectations which may or may not be fulfilled on the facts of each case.