The US has imposed 50% tariffs on some goods from Canada, and the country’s prime minister, Mark Carney, has vowed to match them “dollar for dollar” after the collapse of trade talks.

The tariffs came into force on about $20bn (£14.6bn) of goods – ranging from hockey sticks to tongue depressors – at 04.00 GMT. Trade experts said the tariffs could result in some job losses, but the largest impact is expected to be political, driving a further wedge between the traditional allies.