[illliillll]

Your legal name is whatever you want it to be at any given time, you can just order a new passport or drivers license with ~whatever name you want written on it.

For a passport, the only real requirement is vague evidence that you actually use the name.

[wizzwizz4]

You can also have multiple names listed on your passport: for example, if you have a public and private name, or if you're a noble. I've found that the "vague evidence" requirement is actually quite strict, though: even if you use a name in 95% of everyday contexts, the passport office only counts bureaucratic evidence, and there are circular dependencies with most bureaucracies unless you produce a deed poll (which requires you to attest that you only have one name, for some reason: I'm not familiar enough with the law to know whether this is a real requirement, or just ceremonial language like the "I promise that a Catholic will never succeed to the throne" bit in the coronation ceremony). So the de facto rules about passport names are stricter than names in general.

[GJim]

> drivers license

Oi! It's a Driving Licence here in Blighty!