.uk domains don't have a lock, and are always in your name. .uk domains are transferred by the existing registrant (you) changing the domain's IPSTAG, via your registrar (us) or Nominet.

There is no lock, and no need to contact Nominet to put a .uk domain into your name. They already are, presuming that you're the owner and submitted the correct details at registration time. You can't just transfer someone else's domain at will.

You can never transfer someone else's domain, regardless of the extension. Even if a .com is unlocked, for example, you still need the EPP code and confirmation from the current owner. The lock is an *additional* security method.