The long run, admittedly only sixteen miles. Finished in a reasonably dreadful 3:42, and the rain mostly held off. Were I to keep that pace up I'd finish a marathon in just over six hours.
After eleven miles, I found myself dropping to a walk much more frequently and for longer periods. The worst point was passing thirteen miles, where it occurred to me that in a week I'd be doing another thirteen starting here.
I'm learning some things though. For instance I'll go through the litre of water I bring with me in seven to ten miles, less if it's sunny; and running without water isn't good. I'll become hungry after about five miles. May address both of these by trying some sugary drink though.