Sorry, I'm not going to reply directly to some of the great posts above, but it's always really good to be made aware of the state of crags out there, and other places - and the efforts made to clear them up.
This post is about two years (really?!) overdue.
First of all, we've lost a Neil. If it's you, please 'fess up to an amazing effort, clearing the river bank at the end of Leyburn Road in Sheffield.
There are now a few separate groups of litter pickers in Sheffield, and certainly where we are in Nether Edge in Sheffield, there's an increase in efforts to protect the urban landscape.
A couple of years ago, I cleared the slope to the river Sheaf with Justin Petifer. We were planning to do this again, in conjunction with Sheffield litter pickers, but mystery Neil stepped in for a solo effort. I'll try to get more recent photos.
Here's Justin in 2019:
More rubbish collected by Sheffield Litter Pickers:
I know there are other climbers, active with the litter groups locally, and there are other groups campaigning successfully, to help preserve the river environment too.