A child’s name is an important matter
The courts must see a child’s name, and any proposed change of name, as an important matter; and any change of name must not be undertaken lightly.
This was one of the outcomes of W v A (Minor: Surname)  Fam 14, in the Court of Appeal (at least with respect to surnames). At that point in time, it wasn’t clear whether changes of surname should be considered as important or not, as Lord Justice Dunn explained in his judgment —
When the question of the change of name came before the learned Judge [in the County Court below], he was faced with the dilemma that there are two apparently conflicting lines of authority in this Court on the question of changing children’s surnames. The first is that the change of a child’s surname is an important matter, not to be undertaken lightly [as in the case of re W.G.]. The second is that the change of a child’s surname is a comparatively unimportant matter [as in the cases of R v R (Child: Surname)  1 WLR 1256 and D v B (orse D) (Surname: Birth Registration)  Fam 38]. The learned Judge, faced with the choice between those two lines of authority, opted for the first. The primary ground of this appeal is that in so doing he erred in law.
Lord Justice Dunn wholeheartedly agreed, in his judgment, with Mr Justice Latey who had held, in the earlier case of L. v F., The Times, 31st July 1978, that —
Until the two recent decisions expressed by Lord Justice Stamp and Lord Justice Ormrod [namely, R v R (Child: Surname)  1 WLR 1256 and D v B (orse D) (Surname: Birth Registration)  Fam 38] the prevailing view, enunciated in re W.G. and which had never been questioned, was that on the failure of a marriage a decision to change children’s surnames should never be taken unilaterally and that unless parents were in agreement a decision about it should be approached by the Court as a matter of real importance.
Lord Justice Dunn (in W v A) ultimately deemed the dicta in the cases of R v R and D v B to be obiter — and agreed with the judge in the court below him — in that —
When considering the question of a change of name, that is to be regarded as an important matter …
— and that —
[The judge in the County Court below] approached the matter by preferring the approach of Lord Justice Cairns in In re W.G. [that is — that “the change of a child’s surname is an important matter, not to be undertaken lightly”] to the approach in the obiter dicta in the cases of R v R and D v B [that is — that “the change of a child’s surname is a comparatively unimportant matter”], and in my judgment in taking that course he was right.
In the case of Re F (Children: Surname)  2 FLR 837, Lord Justice Ralph Gibson — applying the principle laid down by Lord Justice Dunn (in W v A) — allowed an appeal on the basis that the judge in the County Court below had not held the matter of the change of name as an important matter. He held that —
Since the fact of changing a child’s name is to be treated as a matter of importance, this Court, if it is clear that the judge failed to treat it as such, as I think it is clear, must set aside the result of the exercise by him of the Court’s discretion and consider the matter afresh.
Lord Mackay, in the House of Lords, in Dawson v Wearmouth  UKHL 18, also upheld the same principle, in that —
The name of a child is not a trivial matter but an important matter, and is not a question to be resolved without regard to the child’s welfare.
The case of Dawson v Wearmouth was a matter of a change of surname only (as with Re WG, R v R, D v B, W v A, and Re F) — although both Lord Justice Dunn and Lord Mackay did, anyway, say “the name” of a child, rather than just “surname”. However, it was held in the more recent case of Re W (Children)  EWCA Civ 1488, that the legal test, applying the principles of Dawson v Wearmouth, applies to changes of first name, as well as to changes of surname.