Sometimes it wasn't so dramatic, but the convoy would still come to an unplanned halt. This time it was mechanical problems with one of the TCHDs (Truck, Cargo, Heavy Duty). Not the sort of thing to be fixed in a layby on a busy single-carriageway road, especially when the layby isn't long enough to accommodate the whole convoy.
"I knew we shouldn't have let our A.A. membership lapse!"
"Do you think we'll still be here at closing time?"