BA (& QF, and others) collect YQ fuel surcharges on their segments which are supposed to reflect such changes. If fare increases are blamed on oil prices, then we should all examine the YQ surcharges closely for a corresponding reduction
from what I read in the media (or what all the airlines said), fuel surcharges are only able to help offset
part of the oil price increases...that's why despite having charged ever-increasing fuel surcharges in the past few years, CX has just issued a profit warning and announced this latest round of fare increase.