What is going on here? I asked a friendly person with an official jacket. All those plastic bags are the runner's clothes and other equipment. All bagged up and numbered, to be collected on finishing. The things organisers have to arrange. If you had asked me, I would have said that the runners turned up at Greenwich in their running gear, and were met at Westminster by friends and family with coats and drinks. On further reflection, I would have realised that was silly, and that yes, runners would turn up in coats, tracks suits and with stuff to wear on the way home. Also food, probably. Which they couldn't leave in Greenwich.
There were a LOT of these trucks.
The front runners were arriving as I was trying to get to St James's station. What surprised me was the size of the gaps between the front runners. There might be four in one little bunch, then a thirty-second gap to a single runner, then a twenty second gap to a pair pacing each other... it wasn't a steady stream, nor a large crowd, as I suppose would have appeared an hour or so later. The elite runners really are running each in their own bubble: high performance is not social.