As per my post in another thread:
http://www.flyertalk.com/forum/briti...w-lay-out.html
and as many others have found out; flying from other airports to LHR then on to USA can save a fortune. There are a lot of threads about quick turnarounds (very easy at AMS): fly LHR-AMS; get out of the gate; turn around; board the same plane back to LHR and on to final destination. In CW this can save you GBP 1000 easily. On your way back from the USA, have your checked luggage labeled to LHR, "miss" your connection to AMS and voila you are on your way home. Some FT'ers think this is against the rules and will protest vehemently about this (mis)use of pricing rules.