I am at Heathrow, and my 20:10 BST flight has become a 22:55 BST flight, meaning I will get into Hamburg at around 01:00 CEST tomorrow.
Gives me some time to write my final impressions of London.
London is a very busy world city. For a small town boy, I think I did remarkably well in it. I used the Tube on my own for the first time this trip and realized just how well the system works.
However, the lasting impression I will have is of diesel. The smell of diesel permeates London. In the office, the hotel, the trains, the cabs, the client offices. Everywhere there is diesel. For someone who is sensitive to strong smells, this is a living hell. I know that it was clouded over and the weather did a lot to accentuate the smell, but I can smell it still here at the airport.
Other than that, the city is a grand dame, unrivalled anywhere. Old and new seamlessly blend, creating a flowing organic place to walk.
I walked along Carnaby Street and Savile Row in the same day.
I saw Glasgow and Edinburgh, as a visiting businessman, not a tourist.
In London, you will hear most of the major languages, within 5 minutes, on the same street.
It is a wonderful and frightening place.
It is complex and simple.
It is like a fine whiskey: repulsive to some, loved by some, and definitely an acquired taste for most.
Off to Hamburg.
UPDATE: Flight now set to depart at 21:15 BST