Campaigners are celebrating today after Joe Biden axed tariffs on British steel.
The 25% duties will be scrapped from June - five months after the White House abolished measures against steel from the EU.
Tariffs were introduced in 2018 under Donald Trump.
Shadow International Trade Secretary Nick Thomas-Symonds said: “This is a long-overdue step.
“UK steel and aluminium manufacturers have had to face four years of punitive tariffs initially imposed by President Trump.
“Ministers have dithered and delayed, so finally getting these tariffs lifted is a welcome relief.”
US tariffs were first introduced for EU steel - including from the UK - on national security grounds under Section 232 of the 1962 US Trade Expansion Act.
The US axed duties on steel from the EU on January 1, but Brexit meant the UK was carved out of the deal and tariffs remained on British-made steel crossing the Atlantic.
Duties on Japanese steel sent to America will be abandoned from April 1 - but Britain will have to wait another two months.
Under the deal, Britain will receive an annual duty-free import quota of over 500,000 tonnes of steel "melted and poured" in the country, with higher volumes subject to the 25% tariff.
The agreement requires any UK steel company owned by a Chinese organisation to audit their financial records to assess influence from Beijing and then share them with Washington.
The requirement will initially apply to British Steel, acquired by China's Jingye Group in 2020.
Industry chiefs have been frustrated with the pace of lifting measures against UK producers.
Community steelworkers’ union operations director Alasdair McDiarmid said: “To protect jobs our steelmakers must compete on a level playing field, and it is vital the UK does not suffer a further competitive disadvantage with EU producers.
“The EU secured their deal with the US back in October, so a UK-US deal is well overdue, and it must be implemented without delay to prevent further damage to our industry.”
UK Steel director-general Gareth Stace said the deal “represents a hugely positive outcome and is warmly welcomed by the UK steel sector”.
“Without this agreement UK producers would have remained at a significant competitive disadvantage in US markets to competitors in the EU and Japan, with their exports severely curtailed,” he said.
“The United States represents a key export market for UK producers but since the introduction of Section 232 tariffs by the previous administration, steelmakers across the UK have been selling into the United States at a huge disadvantage.”
US Commerce Secretary Gina Raimondo said the pact “brings our countries closer together and represents a win-win for both businesses and consumers in the US and the UK”.
International Trade Secretary Anne-Marie Trevelyan said the announcement was "good news for our steel and aluminium industries", which she claimed had been "unfairly hit" by the tariffs.
"It means our manufacturers can now enjoy a high level of tariff-free access to the US market once again," she added.
