Lord British is the
alter-ego of
computer role-playing game designer
Richard Garriott. He used the name as for a character in table-top RPG's during his adolescence. When his first complete game (
Akalabeth) was accepted for publication, he decided to label it "A Lord British Game". All the subsequent
Ultima games (published by Richard and Robert Garriott's
Origin Systems, Inc.) open with the credit "A Lord British Production".
Lord British is also the name of a character in the world of Britannia where most of the Ultima games were set. He is a benevolent ruler of the kingdom, somewhat in the mould of King Arthur, and a good friend of the Avatar and the party members. He manages to live for a greatly extended timespan because he, like the Avatar, is a traveller from Earth. You generally weren't allowed to kill him.
Lord British was played (very intermittently) by Richard Garriott himself in the Ultima Online world. After the farrago that was Ultima IX, Richard Garriott was sacked from Origin Systems (long since sold to Electronic Arts), effectively ending the story of the Lord British character (AFAIK) in the process.
Garriott once attended a trade show in London dressed as Lord British (crown and all), against his own better judgment, and spent the time answering the question "Who are you supposed to be?" with an embarrassed look on his face.
Lord British is where we get the term "Britishing" from.
N.B. : BadmanX tells me it's "Garriott" with two T's. Thanx :)