Yeah, even small airports like Belfast City have had it for the past couple of years. Other London area airports (Luton, City, and Gatwick - not sure about Stan

Yeah, even small airports like Belfast City have had it for the past couple of years. Other London area airports (Luton, City, and Gatwick - not sure about Stansted) have had it for about as long, too. Heathrow's definitely a straggler - I'm assuming it was a more difficult project for them due to their sheer size.