Anyway, I spent part of yesterday clearing litter from the path connecting our stairwell's backgreen to the communal area. I left behind any biodegradable litter, such as wood and also anything that was being used as a home by woodlice etc. The photo below shows the path after I had cleared the brambles, nettles and overhanging branches but before I had cleared the litter. The gardens either side of the path belong to other stairs in the block and I can't do anything with those other than prune overhanging branches and remove the worst types of weeds and litter that are at the edge of the path.
The next task is obviously to do some more weeding. I'm a reluctant weeder, because I like plants too much but the path just doesn't look nice (though at least its really a path now!). I'm also going to sow seeds in some of the verges once I've weeded. I'll buy a packet of shade tolerant wildflower seeds and sow next Spring.