I worked on secondment to Thames Water back in 2011 for 6 months on this, would have loved to do this.
A short while ago, the entire M32 into Bristol was shut for about 24 hours for works in the pandemic. Some folk cycled & skateboarded down it, wish I'd done that just for the memory. I did a night shift once on the M4 outside Swindon, they shut a section between junctions. I collected a water bowser from J17, had permission to drive through the traffic management barriers (thoughtfully opened for me) and found myself driving towards London on the wrong side of the M4, essentially in the fast lane. Even though I knew the TM was on at the other junction, driving along to site in the gathering gloom, I expected a ton of traffic coming headlong towards me