LONDON (Reuters) - Britain will not impose retaliatory trade tariffs in response to U.S. duties on all steel and aluminium imports which are due to come into force on Wednesday, a British government official said on Tuesday.

While the European Union plans to hit back against the 25% US tariffs on imports of the metals, the official - who asked not to be identified - said Britain would continue to engage with the U.S. in an attempt to secure an exemption.

Prime Minister Keir Starmer's official spokesman said on Monday that the UK and the US had a strong economic relationship which was "based on fair and balanced, reciprocal trade."

U.S. President Donald Trump said during a visit by Starmer to the White House last month that his administration and Britain would negotiate a trade agreement which could help to avert U.S. tariffs.

Britain's trade minister Jonathan Reynolds made the case for a British exemption from tariffs to U.S. Commerce Secretary Howard Lutnick in a recent phone call.

The U.S. accounts for about 5% of UK steel exports and 6% of aluminium exports, according to British government data.

U.K. steel exports to the United States are worth over 400 million pounds ($518 million) a year, according to industry body UK Steel which has said the introduction of U.S. tariffs "would be a devastating blow to our industry".

($1 = 0.7727 pounds)