Londinium is from a show that needs to do a better job of naming planets - Firefly. And by doing a better job, I mean making them stick in my head because I had to resort to Wiki to remember any of them. Shame, shame, Whedon. How am I to talk about your show if I can't name the settings? *ahem*
(Actually, looking at these wikia sources, all the information comes from places other than the show. Dang. Oh well, most of Firefly I guess could be said to take place in The Black and it's a show I highly recommend. Wa~tch it! Tis only one season.)
In Firefly, a sf western, for lack of a better term, Londinium was one of the first planets colonized after the mass exodus from Earth. It also, in my mind quite amazingly, housed some of the old museums from Earth.