United Kingdom government sources have said no immediate counter-measures will be taken after the United States imposed a 25 percent levy on steel and aluminum imports.
Previously, US President Donald Trump's tariffs had only been applied to China, Mexico and Canada, but from Wednesday they became global measures.
The European Union, which sent one-fifth of its steel exports in 2023 to the US and which relies on the country as its second-largest market for aluminum, said the move was "unjustified" and responded with what it called "swift and proportionate" measures on a variety of US goods.
But having spoken to Trump about the issue on Monday, UK Prime Minister Keir Starmer had been hopeful talks he had last month about a wider possible trade deal with the US might give the British steel industry some breathing space.
In 2024, around 7 percent of British steel exports in terms of quantity, and 9 percent in terms of value, went to the US, trade the Financial Times newspaper said was worth more than 400 million pounds ($517 million).
Business Secretary Jonathan Reynolds called the tariffs "disappointing" but said the government was "focused on a pragmatic approach" and was negotiating a trade deal with Washington.
During Starmer's February visit to the White House, Trump said a "real trade deal" could happen "very quickly", but in his first term of office in 2019, he also said talks over a "very substantial" deal with the UK were under way, but nothing happened.
At a business roundtable on Tuesday, shortly before the tariffs came into operation, Trump said they may be increased, in a bid to encourage companies to move their manufacturing to the US. "The higher it goes, the more likely it is they're going to build," he said.
Even before tariffs kicked in, UK trade associations reported business had been impacted.
Chrysa Glystra, director for trade and economic policy at lobby group UK Steel, said some producers were seeing their "commercial position in the US being challenged", while Nadine Bloxsome, chief executive of the Aluminium Federation, reported "early signs of business uncertainty".
As well as exports being hit because tariffs made them less desirable, there is the concern that disruption to the global steel trade caused by goods being diverted away from the US could flood the UK market with cheaper imports, causing more economic pressure.
Sharon Graham, general secretary of the Unite union, said the UK government should "act decisively to protect the steel industry", and that the public sector should always buy United Kingdom-produced steel.