There was a course, which I can't remember the number of now (E3 maybe?), which ran along the south side of the Thames. People used to go down there and knock two or three minutes of their PBs, due to having the prevailing wind blowing you one way and lots of lorries sucking you along the other way.
I never rode it but I did do the E4 (revised), which ran along the A13, to the north of the Thames. That course had no lorries! I still have my start sheets actually. I may scan some of them later and post them, as they make interesting reading.