Not sure it's him either. Just seen a Robert Hughes biography on the web and I reckoned that he (Robert Hughes) would be in his forties at the time of the advert. The chap I'm thinking of looked much older. I could be wrong though, Robert Hughes looks a bit grumpy too. thanks anyway Jay-jay (and to Kempie!)
Could it have been a veteran CBC anchor called Earl Cameron? His biography mentions Krona margarine. Sadly, he is no longer with us, but I remember the ad very well. He was in a town called Broken Hill and I think he said something about questions were raised in Parliament about Krona margarine.
definitely not old Arthur C. I've heard other's mention him but the best lead so far seems to be Earl Cameron from Stenocaption, I have a vague memory of the chap standing in a hot and dusty town (Broken Hill) and in the outback in a safari suit, or the Austrlaian equivalent, telling us that questions were asked in the Australian parliament about Krona margarine.