DONALD TRUMP’S plans to impose tariffs on steel should be a “wake-up call” for the government, Unite warned yesterday, as it called for rule changes to prioritise home-produced steel.

The US president said he would impose 25 per cent tariffs on steel and aluminium imports into the country.

Mr Trump has not confirmed if Britain will be hit and said he will make a formal policy announcement later this week.

But Unite reiterated calls for Britain to better protect the industry by transforming public-sector procurement rules to ensure that all British infrastructure projects use home-produced steel whenever possible.

It argues that this would be legal under existing trade rules if it were to be designated “critical national infrastructure.”

Unite general secretary Sharon Graham said: “I have long been calling for the steel industry to be classified as critical national infrastructure — just as it is in the US. 

“UK steel production is a matter of national security. We now need to change the rules to ensure that the public sector buys UK-produced steel, wherever it is available. This will create jobs and drive growth.

“Instead of leaving our security and our steelworkers open to the whims of other countries, we should be protecting our domestic steel industry from unfair competition and ensuring that we can transition into a leading producer of green steel.”

Community union said tariffs on British steel would be hugely damaging for Britain and self-defeating for the US.

Alasdair McDiarmid, Community’s assistant general secretary, said: “The comments from the White House regarding new tariffs on steel are extremely concerning.

“At a time of uncertainty for the sector, a punitive new tariff on UK steel exports would be hugely damaging and threaten jobs. 

“For the US it would also be self-defeating, as the UK is a leading supplier of specialist steel products required by their defence and aerospace sectors.”

UK Steel, which represents the sector, warned that the tariffs would initiate a “devastating blow,” noting that the US is Britain’s second-largest export market after the EU.

Director-general Gareth Stace said: “At a time of shrinking demand and high costs, rising protectionism globally, particularly in the US, will stifle our exports and damage over £400 million worth of the steel sector’s contribution to the UK’s balance of trade.”

Home Office minister Dame Angela Eagle said the government would have to “wait and see whether the president gets more specific about what he meant by that comment.”