Got caught by the fog on the way back from Madrid on Wed. Only after we got onto the plane (and weren't allowed off, even mom with her fretting toddler) were we told that there would be a 3 hour delay in departure! Heathrow was rather chaotic by the time we arrived around 4 pm. Thank goodness I could use the Club/First desk for Flight Connections - although it had only 2 staff (who were moving at quite a leisurely pace). I decided not to bother with trying to make 16 connections in order to get back to NA asap, and opted to take a flight the next day. Went into central London to find a hotel (not paid for by BA because the fog was an Act of God), then went shopping. In driving back to LHR the next day, it was was extraordinary to see how the fog suddenly appeared about 2 km from the terminal - it was a relatively clear day and then, suddenly, instant fog. Presumably the same thing had happened the day before. Happily - got upgraded to 1st on the way home. I figured I was due for this kind of problem - I'd narrowly avoided being caught up in the BA wildcat strike at Heathrow (thanks to a warning from this board) and also just missed getting caught up in the delays due to the LA fires in October) - and it didn't inconvenience me because I was on my way home from a meeting. I'm hoping that it still counts for "delay karma" points, though, so that I can count on problem-free travel for a few more months.