Canada’s top spy reviewer resigned on Thursday following revelations by the National Post that he was involved in business dealings with a shady Montreal consultant and had uncomfortably close ties to the president of his native Sierra Leone. Dr. Arthur Porter, an oncologist and hospital administrator, had been federally appointed chairman of the Security and Intelligence Review Committee, which acts as a watchdog of the Canadian Security Intelligence Service. “Dr. Porter has submitted his resignation to me, and I have accepted it, effective immediately,” read a statement by Prime Minister Stephen Harper released on Thursday.