UK departure taxes are the highest in Europe and the taxes out of LHR are the highest. That is why there are ways open seats out of LHR. People in the know usually non rev INTO lhr then out of somewhere else. Nothing nefarious going on, just governmental taxation without representation (tourist have no vote other than not to travel there)!! LOL. Do an Internet search. It's easy to look up the departure taxes from various European cities and plan accordingly.