Change of name law
Your legal name, in the U.K., is the name you are generally called and known by.
Henry de Bracton wrote, in his De Legibus et Consuetudinibus Angliæ (c. 1235) folio 188b —
And so if a person has two names, whether in his name or in his surname, that name is to be adopted by which he is more frequently accustomed to be called: because they are imposed for that reason, that they may show the intention of the speaker, and we make use of speech as a servant.
In the case of Davies v Lowndes (1835), Chief Justice Tindal held in his judgment that the defendant (Mr Lowndes) had validly changed his name to Selby, by simply taking and assuming the new name —
It has been more than once asked by a learned gentleman of the grand assize, whether the name [of Mr Lowndes] has been changed in the way which the law prescribes. In this will the condition is, that Mr Lowndes changes his name to Selby. It appears, that at first he retained the name of Lowndes, while the receivership was going on; and that afterwards he took the name of Selby in addition to the other; and I am not prepared to say that that was not changing his name: but at all events he afterwards changed it entirely, and left out the name of Lowndes. There is nothing in the will that purports that the condition is to be executed in a very limited or precise time; therefore, though he took it a little later, and though in some particular acts he might use the other name, it would not at all interfere with the general act of changing his name. And there is no necessity for any application for a royal sign manual to change the name. It is a mode which persons often have recourse to, because it gives a greater sanction to it, and makes it more notorious; but a man may, if he pleases, and it is not for any fraudulent purpose, take a name and work his way in the world with his new name as well as he can.
And in 1901 (that is, much more recently), in the case of Cowley (Earl) v Cowley (Countess) (1901) 85 L.T Rep. 354, P. 1900, 118,  A.C. 450 — in the House of Lords (sitting as the Court of Appeal) — Lord Lindley held, in the same way, that —
Speaking generally the law of this country allows any person to assume and use any name, provided its use is not calculated to deceive and to inflict pecuniary loss.
First name and surname
In fact it isn’t a legal requirement to actually have either a first name or a surname. The law presumes that you do have a name (see: Wakefield v Mackay, falsely calling herself Wakefield (1807)) — as is usually the case — but it isn’t technically speaking a requirement. Nevertheless — as a person is normally called and known by something — in practice, a person will always have a name of some sort.
It’s also possible to have a single name — that is — one name only, which doesn’t consist of a distinct first name and surname (although the single name could still consist of more than one word or name).
A person’s legal name and surname is not something which is formally defined by statute — it is something which has been established by case law, by the doctrine of precendent (going back hundreds of years).
The law governing birth registration in the U.K. is complex enough that we’ve written about it separately.
The registration of births is a devolved matter for England & Wales, Scotland, and Northern Ireland. However, in each jurisdiction, parents must register their child’s birth within a certain number of days, and truthfully declare the name and surname that they’ve given their child at that point.
Birth registration merely records the name of a child on the day of registration — it’s not the act of registration itself that gives the child their name. The child can still have a name before the registration, and can have their name changed after that point. Furthermore, each jurisdiction in the U.K. allows for a name to be given in baptism after the birth registration takes place.
Consequently, a birth certificate doesn’t prove what your current name is, but together with a chain of documentation proving how your name has been changed up till the present day, it can be used as proof of identity (e.g. when applying for a passport).
When you’re known by more than one name
In cases where a person has been known by more than one name (for different purposes, or to different people) — or where a person has changed their name many times over a short period of time — it can be difficult to know what that person’s legal name is.
It is an ancient part of the common law that a person can only have one given name (or “Christian name” — although this has been interpreted to mean the given name, whatever that is, even for non-Christians), but that a person may have more than one surname.
However, when the law asks for one name only (or the “true name”) of a person, the courts have had to decide how that should be interpreted.
In these sorts of cases the courts have generally held that —
- a person’s name and surname is the name and surname they are generally called and known by
- where there is doubt, or where many names are used (or have been used) — the name (or names) that are used for formal, solemn, and official purposes — over a substantial period of time — are preferred over names that are used for temporary, social or day-to-day purposes
Examples of formal, solemn, and official purposes would be —
- birth registration
- baptism and confirmation (as to forenames only — as baptism is not concerned with surnames)
- marriage (and divorce proceedings)
- other legal proceedings
- formal identification documents such as passport / national identity card
- driving licence
Although the courts have held that “any one may take upon him what surname, and as many surnames as he pleases”, this doesn’t mean that you can assume a new name on a whim, at any time. This was held by Sir William Scott in the case of Wakefield v Mackay, falsely calling herself Wakefield (1807), where one of the parties to a marriage had been known by five different surnames in a short space of time — and the court had to consider whether the “true name” had been used in the proclamation of banns (according to the Marriage Act 1753).
In his judgment, Sir William Scott held that —
The marriage, except in case of a licence, is to be performed by proclamation of banns, which is to designate the individual, in order to awaken the vigilance of parents and guardians, and to give them an opportunity of protecting their rights. [The Marriage Act 1753] therefore requires that the true name should be given to them, evidently considering that a name, assumed for the occasion, is a name that will not answer the purposes of the provisions.
Sir William Scott then held that — if the court had to choose one name as the “true name” (out of the five possibilities put forward) — that in its consideration, more weight should be given to the name (or names) which were used at birth, and for formal, solemn occasions (both religious and civil) —
Taking all this evidence together, that [“Jackson”] was the name of her mother; that it was the name impressed upon her at her birth; that she has used that name in the most solemn acts of her life, civil and religious, and at various periods of her life, which has not been a long one; I say, taking that evidence, and comparing it with the evidence on the other side, which embraces only a very short period of her eventful life; the Court would not be warranted to say, upon this evidence, that Jackson is so clearly demonstrated to be the untrue name of this person, if she did possess a true name, as to destroy the validity of the marriage.
A child’s name can be changed in the same way as an adult’s, except that it is the right and responsibility of whoever has parental responsibility for the child to decide if and when their name should be changed.