If Heathrow is full then whop the prices up - straight capitalist economics.....
Already been done, but capitalism is long gone, it's been replaced by "corporate cronyism".
All points of arrival within the GLA or TFL area are on the meter.
Do they not cover the same area? Isn't TFL a department of the Mayor's Office/Greater London Assembly, rather than a geographical entity, a new name for what used to be London Regional Transport?