Mystery solved

It was the neighbours.  When I left the house this morning, the green bin was sitting out on the roadside, filled to the brim with branches from the tree I saw the neighbours cutting down at the weekend.  As were all my other neighbours’ bins.  They’d obviously run out of room in their own bin and “borrowed” everyone else’s.  Oh well, at least they returned it before I rang the council to report it stolen.  Would have been nice if they’d left a note, though…