May said in a statement that the United States, the European Union and Britain are close allies and have always promoted values of open and fair trade across the world.
The U.S. has a shortage of domestic supply of steel and aluminum, while prices have risen nearly 40 per cent since Trump announced tariffs in March, when he temporarily exempted Canada. Trump has regularly complained that other countries impose higher tariffs on imported vehicles than the USA does. "Congress can not sit idly by as Donald Trump continues to isolate the United States and cede leadership to Russian Federation and China on the global stage". When President George W. Bush in 2002 raised steel tariffs to protect against a surge in imports, they created a slight $30.4 million drag on U.S. gross domestic product, according to the U.S. International Trade Commission.
Washington cited national security reasons for the tariffs.
British Prime Minister Theresa May has said she was "deeply disappointed" at the unjustified decision by the USA to apply tariffs to European Union (EU) steel and aluminium imports.
"Canada considers it frankly absurd that we would in any way be considered to be a national security threat to the United States", Canadian Foreign Minister Chrystia Freeland said before the tariffs were announced.
U.S. Commerce Secretary Wilbur Ross is leaving Friday for Beijing for talks aimed at preventing a trade war with China.
The Wolfsburg-based company is calling for dialogue between the USA and the European Union within recognized World Trade Organization principles "in order to prevent any long-term economic damage". Canada and its European allies have spent recent days making a concerted effort to head off the move.
Brussels has previously threatened to slap tariffs on United States products including bourbon, motorcycles and blue jeans.
Fears of a global trade war are overshadowing the G7 talks in the Canadian resort town of Whistler, as Washington's allies vow to push back against the USA decision on tariffs.
Mr Stace told BBC Radio 4's World At One that it was too early to speculate on the likely impact on jobs, but said: "At worst, we could fall straight back into the crisis we suffered in 2015/16, which was the worst steel crisis in a generation".
Public companies may feel pressure from shareholders who would expect them to fight the US government in court and get an injunction, he said in an interview.
In Canada, Prime Minister Justin Trudeau said the tariffs were "totally unacceptable", and Canada announced plans to slap tariffs on $12.8 billion worth of USA products, ranging from steel to yogurt and toilet paper.
In a March 2 Twitter post, he declared trade wars "good, and easy to win", though later he denied the US and China are in one.
The U.S. action widens a rift with America's closest allies, threatens to drive up prices for companies and consumers that buy steel and aluminum, heightens uncertainty for businesses and is already alarming investors in global financial markets. "We are expecting everybody to play by the rules".
Finance Minister Bill Morneau said in a statement late Wednesday that Canada has expanded the scope of its country of origin marking regime for steel and aluminum products to better determine where they come from.
But as part of the efforts to address outstanding trade disputes, Europe will present a complaint before the World Trade Organisation against China's intellectual property practices, it confirmed on Friday.
United Kingdom steel producers could be shut out of an American market where they sold around £350 million of exports previous year, while also facing increased competition from a "tsunami" of cheap steel diverted away from the U.S., he said. But German Economy Minister Peter Altmaier insisted the Europeans were ready to negotiate special trade arrangements, notably for liquefied natural gas and industrial goods, including cars.