Canadian Prime Minister Mark Carney said on Saturday he would slap retaliatory tariffs on the United States after walking away from a “bad deal” on trade, deepening the rift between the long-time allies. Negotiations between the neighbouring countries broke down on Friday in Washington, allowing new 50 per cent US tariffs impacting some US$20 billion worth of goods, or 5.5 per cent of Canadian exports to the United States, to come into force.