Given the close links, in particular between the 2000 Convention and the 1996 Child Protection Convention, as explained in the Lagarde Report; given the relationship between the 2000 Convention and the MCA; and for general policy considerations as referred to by Lady Hale in A v A, it is clear to me that the definition of "habitual residence" under the MCA should be the same as that applied in other family law instruments, including BIIa. Further, BIIa is also closely linked to the 1996 Convention, as explained in Proceedings brought by A.

In my view, it must be right that the approach to the issue of habitual residence under BIIa should be the same as that under the MCA. I have not been directly referred to other judgments from the Court of Justice or domestically which address the issue of habitual residence including those which refer to the test of "centre of interests". However, this phrase is incorporated in the judgment of Mercredi v Chaffe, as referred to above. Accordingly, whilst, inevitably, different factors will be relevant and will bear differential weight, the overarching approach should be consistent across all international family law instruments, including under the 1996 Child Protection Convention and in respect of children under BIIa. Any other approach would, in my view, be inconsistent with the points made in the Lagarde Report, especially in paragraph 49.

I do not, therefore, accept Mr Rees's submission that the approach established by the CJEU, as adopted by the Supreme Court, is not applicable. I agree with Mr Harrop-Griffiths that the test should be the same, suitably applied, as that under Brussels IIa as referred to above. If a different approach was to be taken as between adults and children, habitual residence would not even be applied consistently within BIIa. It is plain that different factors, as in any case, will or may have differing degrees of relevance. But, in my view, the overarching test should be the same.

However, I agree with Mr Rees's submission that the Local Authorities have adopted too narrow a focus when addressing the circumstances of this case. It is clearly important, given its critical place in so many international instruments, that the determination of habitual residence is kept as free as possible from analytical complexities or constructs. It is a question of fact. In my view, the Local Authorities in the present case have focused unduly on whether SW is integrated, in the sense of settled, by reference to whether she is happy living where she has been. Reduced to their key elements they submit that, given SW's placements in England have to varying extents been determined for her and given she does not like living where she is, SW is not habitually resident in this jurisdiction because she has never become sufficiently integrated.

Although the Supreme Court refers, in both A v A and Re LC, to the test or question as being whether there is some or sufficient degree of integration in a social and family environment, I do not accept that this was intended to narrow the court's focus to this issue alone as an issue of fact. It is not a free-standing, determinative factor, and in particular not to the exclusion of all other factors. In my view, this would not be consistent with the broad assessment identified as being necessary by the CJEU. As the Court said, in Proceedings brought by A, the national court must conduct an "overall assessment" in the light of the factors referred to in paragraphs 38-41.

In Mercredi v Chaffe the Court of Justice said that the place of habitual residence "must be established, taking account of all the circumstances of fact specific to each individual case" (paragraph 47). These include the conditions and reasons for the stay, its duration, and other factors which make clear that the person's presence is not in any way temporary or intermittent. Factors which, as Lady Hale said in Re LC (paragraph 59), address whether the residence has acquired "the necessary degree of stability".

Further, integration, as an issue of fact, can be an emotive and loaded word. It is not difficult to think of examples of an adult who is not integrated at all in a family environment and only tenuously integrated in a social environment but who is undoubtedly habitually resident in the country where they are living. Integration as an issue of fact can also raise difficulties when a court is determining the habitual residence of a person who lacks capacity. As Mr Rees submits, there is a wide range of potential factual situations which will impact on the court's ability to establish a person's state of mind or perception and the weight which can properly be given to it.

To repeat what Lady Hale said in A v A, at paragraph 54(vii): "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 inquiry would produce". Another way, in my view, of expressing this might be that the court should not lose sight of the wood for the trees. I say this because, standing back for a moment, it might be thought surprising that it might be argued that someone who has been living, largely voluntarily, in England for nearly five years, and for the last three-and-a-half years in their own flat, was not habitually resident here.

I would suggest that the phrase "degree of integration", as with centre of interests, is an overarching summary or question rather than the sole, or even necessarily the primary, factor in the determination of habitual residence. Otherwise, it would become a legal construct in place of the essential issue which is, of course, that of habitual residence. This is not to say that the degree of integration and a person's state of mind are not relevant; they are clearly factors to which appropriate weight must be given when the court is undertaking a broad assessment of all the circumstances of the case. The broad assessment which is required properly to determine whether the quality of residence is such that it has become habitual in that it has the necessary degree of stability in order to distinguish it from mere presence or temporary or intermittent residence. This means a sufficient, or some, degree of integration, not, I suggest, as a limited factual assessment, but as a question to be answered by reference to the factors, suitably applied, referred to by the CJEU and the Supreme Court. Determination

Turning then to the circumstances of the present case. As SW has been living in England since July 2009 and has been living in her own flat since December 2010, in my view there would need to be some compelling countervailing factors in order for me to determine that she is not habitually resident in England.

I accept that SW's move to England was pursuant to a compulsory treatment order and that, since then, her place of residence, while seeking to meet her wishes as much as possible, has very largely been governed by the relevant authority's decision as to what would suitable and by what has been available. I also accept that SW has expressed her dislike of the area in which she lives and her wish to move somewhere else. However, I do not consider that these factors come close to counterbalancing the effect of SW's long residence in England especially when combined with the matters referred to by Mr Rees (paragraph 61 above).

By virtue of its duration, SW's residence has, in my view, acquired what might be termed effective "stability", in the sense used by the Court of Justice. Many people would rather not be living where they are and might wish fervently to live somewhere else. However, at least after a person has been living in one place for a significant period of time it will be difficult not to come to the conclusion that they are sufficiently integrated into their environment, whatever its composition, for them to be habitually resident there. In the present case, any other conclusion would, in my view, be placing far too much weight on an assessment on SW's state of mind and the extent to which she feels settled. Accordingly, in my judgment SW is habitually resident in this jurisdiction for the purposes of the Mental Capacity Act 2005.