US President Trump's long-threatened 25% tariffs against Canada and Mexico began at midnight in Washington DC, as did a new 10% levy against China - we break down the tit-for-tat tariffs here China has since vowed to fight the US "to the bitter end" and announced counter measures - which include up to 15% tariffs on a range of American agricultural and food products Canada retaliates with immediate 25% tariffs against $30bn worth of US goods,