Trump has said repeatedly he wants Canada to become the 51st state. It's a statement sometimes laughed off in the U.S., but viewed as deadly serious in Canada.

Canada has unveiled C$29.8billion (£15.9billion) in retaliatory tariffs in response to the 25 per cent steel and aluminium tariffs imposed by the United States. Earlier this morning, US President Donald Trump launched a 25 per cent levy on imports from these industries from across the globe.

President Trump said he would double steel and aluminum tariffs on Canada amid a fight with Ontario over higher electricity costs for Americans.