Blame the Vestey family. They started it when they scarpered off to Argentina to avoid taxes after a bust up with Lloyd-George
If the stories circulating back in the 1960's were correct they did some dodgy deals back in the 1940's with Germany. My father used to cuss them every time we passed one of their shops
(if you wonder who I mean, think Dewhirsts, MacFisheries, Blue Star shipping....)