British and European steel makers are bracing for a fresh crisis in the industry unless the US backs down from its protectionist stance and extends an exemption on import tariffs.

The US granted temporary relief to European producers from 25pc tariffs on steel and 10pc levies on aluminium as Donald Trump, the US president, introduced the measure in a move widely seen as targeting imports from China.

However, the exemption runs out on Tuesday. Wilbur Ross, the US commerce Secretary, said over the weekend that administration planned to extend the relief to some countries, but not all, and refused to be drawn on which ones would remain exempt.

Tariffs would hit steel makers this side of the Atlantic hard, with the industry only just recovering from the 2015 crisis which cost tens of thousands of jobs. Closure of the US market creates the potential for a “double whammy” to the European industry. Not only is America a major market – steel exports to the US accounts for about 7pc of UK steel production and are worth about £330m a year – but Chinese producers are likely to flood Europe with excess output, a major cause of the crisis of three years ago.