The president-elect’s threat to hit Canada, Mexico and China with new tariffs is already rocking business and diplomatic relationships and could topple the trade pacts he signed in his first term.

Britain will aim to convince Donald Trump its services-dominated trade with the United States should escape the worst of tariffs even as it cautiously repairs ties with the European Union and nurtures commercial links with China.

If they are imposed, the tariffs will hurt American consumers most of all. The North American supply chain is integrated; nearly $1trn-worth of goods crossed the northern and southern borders of the United States last year.

On Monday, President-elect Trump specifically promised​ a 25% tariff on all products coming from Mexico and Canada—in addition to a 10% levy on Chinese goods.