Theresa May hits out at Donald Trump for 'unjustified and deeply disappointing' steel tariffs plan in 30-minute phone call

US president sparked fears of a transatlantic trade war by slapping massive tariffs on imports of steel and aluminium

Theresa May has rebuked Donald Trump over his "unjustified and deeply disappointing" plan to impose punitive steel tariffs on US imports, Downing Street has said.

The president sparked fears of a transatlantic trade war when the United States slapped massive tariffs on imports of steel and aluminium from allies including Canada, the EU and Mexico last week.

Ms May's official spokesman said the 30-minute call was "constructive" and both leaders would discuss the issue further at the crucial G7 summit in Canada this week.

Mr Trump originally imposed the tariffs in March, a move he said was motivated by the fact that relying too heavily on imported metals was a threat to America's national security.

But he gave Canada, Mexico and the EU a short exemption for negotiations, which expired at midnight on Thursday.

The PM's spokesman told a Westminster briefing: “The prime minister raised the US decision to apply tariffs to EU steel and aluminium imports, which she said was unjustified and deeply disappointing.

"The prime minister said the US, UK and EU are close national security allies and we recognise the importance of the values of open and fair trade across the world.

"The prime minister also underlined the need to safeguard jobs that would potentially be affected by the decision."

In the Commons, Liam Fox, the trade secretary, faced a Liberal Democrat call for the US to be suspended from the G7 group of advanced economies if it “continues to act like a rogue state”.

And Barry Gardiner, Labour’s shadow trade secretary, urged the Government to “stand up” to Mr Trump, saying: “We do not want a trade war, most rational people believe there are no winners.

“Only President Trump has said he believes he can win one. The UK and the EU must stand up to this behaviour and restore the rules-based system.”

Dr Fox said a “tit-for-tat dispute will help nobody”, warning it was “very easy to see how this ramps up into a global trading disaster”.

However, he said the UK was working with the European commission on plans for retaliatory duties on US goods and on taking the dispute to the World Trade Organisation (WTO).

Dr Fox said the American decision to use national security as a rationale for the tariffs created “a worrying global precedent”.

“Were the United States to be successful it sets a precedent for others do the same and to use national security as pretext for protectionism, and secondly, it leads the WTO into the realms of having to determine what is and what is not acceptable as a definition for national security, something the WTO has always shied away from,” he said.

Gareth Stace, director of trade body UK Steel, said the US tariffs were a “hammer blow” to British producers which will “significantly” undermine their ability to export to the States.

"The top priority for UK Government must be to continue to support the European Commission to secure a complete and permanent exemption for the EU from these absurd tariffs,” he said.

“We dearly hope that this experience does not foreshadow post-Brexit trading for British companies, with the UK isolated and battling over trade issues on different fronts, without the heft of the EU behind us. The prospects are undoubtedly a cause for concern.”