Heathrow Christmas...In May???

Today I left home at 0 dark-thirty and went to the airport for an 'office day'. I was there with my 'Union Hat' on, available to meet and chat with Members before they left on their flights. I also met an incoming crew who arrived as passengers after their trip had gone 'pear-shaped' the day before.

When I was waiting in the arrivals lounge I saw this tree in the distance!  Well, I've always said that Heathrow is one of the first places to put up its Christmas decorations (so people will buy more Duty Free goods), but in MAY???  

Take a look at the Extra photo for the answer to the mystery.