One problem with litter on the towpath is that the bins aren't emptied frequently enough. The bin opposite Wick Village is often full with bags of rubbish around it. These bags soon get torn open by foxes and the litter spread around.
These bins belong to Canal River Trust so I assume they are responsible for emptying them. CRT have said to us that the litter is blowing into the river as the council are not cleaning the streets enough, but I think a lot of the litter originates from around the towpath bins.