LONDON (Reuters) – The businessman appointed by Boris Johnson as Britain’s ‘Cost of Living Business Tsar’ said six months ago that the prime minister was not blessed with intelligence and should quit. Late on Monday, the government announced that David Buttress, former founder and chief executive of online food delivery company Just Eat, would take on a role to help the public with rising living costs. However, on Tuesday heavily critical tweets that Buttress had written about Johnson were reported by media. “Why is it that the worse people often rise to the highest office and stay there,” he …