Well I took it because I was silly enough to buy a flight with a transfer between London City and Heathrow. The first time I took a cab...238 pounds. Kill me. Next time I took the tubes, and was glad to get on the cushy express after the crowded London tubes...and I had to make my flight so another hour would not have worked for me.

Well for clueless tourists like me, I sucked it up and paid up the 50 pounds or whatever it costs for the roundtrip to the airport.