This bracket, possibly the willow bracket, Phellinus igniarius, is now going the same way as the host it finished off. Like the fallen tree to which it is attached, the fungus is now sideways on, with the originally upper surface now on the left.
The tree and its attachments are being left to decay naturally on the pedestrian island on St Andrew’s ringway, right by Chapel Ash roundabout.
The green stains on the fungus and the tree bark is the lichen which is successfully colonising even in this environment.