Professor Slughorn inspired by an Oxford don?

I remember reading somewhere - quite a while ago - that Rowling may have based the character on a certain Oxford (may have been Cambridge) academic. Not a very famous person like, say, Tolkien or EM Forster. Less well known than that (I'd never heard of him before). I suppose Slughorn's little exclusive parties and suppers are reminiscent of that particular socially-elitist university environment generally, but I seem to remember that it was a particular individual. Someone who was rather well known for that sort of thing. Does anyone here know?