I'm an young American actor who just moved to London. Does anyone know if they have the equivalent of Central Casting for background work here? London being expensive like hell, I want to earn some extra money, while doing something relevant to my interest.
In the UK the term is 'extras agency' or 'casting agency'. As mentioned, they will probably want you to pay a fee. You will also need portfolio shots. I know a good photographer in London who does headshots. Reach out to me if you want more info.
There are several extras agencies, but they really want middle-aged and elderly extras - not young people. Look in Yellow Pages.
Also, you have to pay a fee to join, and you're unlikely to ever get more than a day or two's work, here and there, in a year.
If you need to earn money, get a normal job.