A funny sky

Never seen anything quite like this before - it's not a rainbow, because a) it was not raining and had not been recently and b) it was not a bow - just an almost vertical line. It was not a sundog either, I don't think, as that would be smaller and circular. This was taken at 8.45pm facing due South as the sun was setting about WNW
Whatever it was, it gave me a Blip for today!