The United Kingdom is a member state with different legal systems applying in different “territorial units”. Article 66 of the Regulation provides that a reference to habitual residence, or domicile, in a particular member state relates to residence or domicile in the territorial unit in question. The Regulation therefore applies within the United Kingdom. If, for example, both spouses are habitually resident in Scotland (and nowhere else), the Scottish courts have exclusive jurisdiction under the Regulation. Quite why the EU has taken upon itself to provide rules affecting the internal regulation of cases within the United Kingdom is a mystery. The treaty base for the Regulation, allows measures to be “necessary for the proper functioning of the internal market”. It is arguable that the EU have exceeded their powers.
“Habitual residence” is a key concept in Brussels II bis. It is not defined. Habitual residence is a question of fact. It has been said to mean residence which is being enjoyed for the time being and with the settled intention that it should continue for some time (Dickson v Dickson 1990 SCLR 692, see also Nessa v Chief Adjudication Officer  1 WLR 1937). At one time it was thought that in order to be habitual, residence should be voluntary, but the Inner House has indicated that residence need not be voluntary to he habitual (Cameron v Cameron 1996 SCLR 25). It was also thought that the residence should be lawful, but the House of Lords has decided habitual residence may arise even when a person is resident unlawfully (Mark v Mark  3 WLR 111). The House of Lords in Mark went further and held that the term “habitual residence” could have different meanings in different statutory contexts. In Scotland, in the context of international child abduction, the First Division held that a person could only have one habitual residence. In England it was held by the Court of Appeal that for the purposes of jurisdiction a person may have two concurrent habitual residences (Ikimi v Ikimi  2 FLR 1288). The House of Lords in Mark confirmed that a person might be habitually resident in more than one place at a time, or might have no habitual residence at all. The European Court of Justice in Swaddling v Adjudication Officer  2 FLR 184 considered that habitual residence referred to the state in which persons habitually resided and where the habitual centre of their interests was to be found. Account required to be taken of the person’s family situation, the reasons which led him to move, the length and continuity of residence, the fact of stable employment and intentions as appeared from all the circumstances.