Originally Posted by og
If you can manage the itinerary, just make sure you transfer (<24 hrs) in LHR before your long haul back to where you came from. That avoids the big tax - be it GBP 20 or GBP 40. You just get stung with the Euro tax which is a lot less - regardless of class.
Actually, since it would affect me on an upcoming trip to the U.K. where my departure back to the U.S. will be in <24hrs and I've already been UPG'd for the return, I posed the question on the Mileage Run forum. They said a return back to the same country is considered two separate trips, not a connection, so the 20 pound tax (assuming upg from coach) would still apply.