British manufacturers have won a temporary reprieve on 25 percent tariffs being added to steel exported to the United States after the White House announced on Monday night that it was postponing a decision to impose duties on key trading partners for 30 days, avoiding a trade war with Europe

Mr Trump imposed the hike, along with a 10 percent tariff on aluminum, in March but granted temporary exemptions to Canada, Mexico, Brazil, the European Union, Australia and Argentina.

Those temporary exemptions were due to expire at midnight on Monday, prompting last-minute negotiations.

Hours before the deadline, the White House said it had reached an “agreement in principle” with Argentina, Australia and Brazil, and was extending negotiations with Canada, Mexico and the EU.

"In all of these negotiations, the administration is focused on quotas that will restrain imports, prevent transshipment, and protect the national security," the White House said in a statement.