If traveling in economy class, the UK is actually one of the cheapest origin points in the world. In business or first class, forget about it.
One place for discussion about budget RTW travel (and I'm assuming that here) is the Gap Year/RTW forum on the Lonely Planet Thorn Tree -
http://thorntree.lonelyplanet.com/ca...s.cfm?catid=58.
Much of the discussion of RTWs on Flyertalk centers on premium-cabin travel and mileage-earning issues. If your interest extends to those topics, then the "Global Alliance" section of FT is the place to go lurk. Read the sticky threads first, or else you'll become overwhelmed by details, details, details.
And another welcome to FT!