Donald Trump has launched another furious attack on Canada - and threatened to hit the country with tariffs so big they 'will be read about in history books'. The US president stepped up his North American trade war today with a new announcement of steep 50% tariffs on all Canadian steel and aluminium - effectively doubling the measures he had previously announced.

Donald Trump explosively warned Ontario that it would "pay a financial price" for its retaliatory tariffs "so big that it will be read about in History Books for many years to come"

The National Review said it's "unfathomable that we are threatening the sovereignty of a fellow NATO country."