LH rear tyre worn excessively on outer half (B Class / W245)

[twocups]

I realise I need to take the vehicle in to a garage to have it properly assessed, but pre-empting that, any thoughts on what could be causing this curious uneven wear pattern on my LH (nearside) rear tyre? - to the left of the approximate centreline of the tyre, the surface pattern is pretty much worn away (though there's still a reasonable tread depth), while to the right of the centreline, the surface pattern is normal. In other words, there's much more wear going on from the centre to the outside edge of the tyre. TIA.

 

[JBell]

Needs Hunter 4 wheel alignment, clearly the wheel has hit something to cause that much toe / camber