Tunnels under motorway (M4). Nice smooth concrete walls, but gets VERY muddy after heavy rain as the river floods. If it's wet bring wellys. Main wall 11 feet high and 50 feet in length. Not legal but very chilled, middle of nowhere. No problems from locals. Best access is from the end of Old Slade Lane (follow public footpath)
go on mototrway trussst me
Is this wall still safe to paint?