Originally Posted by buck3y3nut
Thanks a lot. I think this is what I will do. Can I just buy the tickets for the tube at LHR itself? Or do I have to buy them everytime before I get on them??? I was checkign the website of thetube and it said something about a day pass or something. then it talked about zones, which totally got me

... anyways, i'm looking forward to this trip...
All you need to know really is that LHR is in Zone 6 and Knightsbridge is in Zone 1.
If you are starting your journey after 9.30am (off-peak), your best deal would probably be to buy a one-day travelcard for Zones 1-6 at LHR. Then you can just travel around all day on it without having to buy any more tickets.