LONDON (Reuters) - Britain has not seen details of U.S. President Donald Trump's proposed steel and aluminium tariffs and will continue to engage with the Trump administration as appropriate, a spokesman for Prime Minister Keir Starmer said on Monday.

Trump said on Sunday he would introduce new 25% tariffs on all steel and aluminium imports into the U.S., on top of existing metals duties, in another major escalation of his trade policy overhaul.

Starmer's spokesman said while it was not possible to speculate on the impact of such tariffs without seeing details, Britain always prepares for all developments.

"I haven't seen any detailed proposals following reporting overnight, but we will obviously engage as appropriate," the spokesman told reporters.

Separately, industry body UK Steel said any tariffs would represent a "devastating blow" to the sector, harming high-end steel exports to the U.S., which is Britain's second largest export market after the European Union.

Britain exports around 200,000 tonnes of steel per year to the U.S., worth over 400 million pounds ($495 million).

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