[197] Wonky bumper @ Left rear

See pics (thumbnail links)




As far as I know there has been no collision to cause this, could it be that a clip/screw is loose or deformed? Much danger of it being the bumper that is deformed? Other side is completely straight with a uniform gap. It doesn't seem loose, trying to push it back into position sees there being no real movement in it at all.
Any thoughts as to how to proceed with checking it out? (not really looked at any bodywork on a car before!)