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Boris Johnson has warned the US president against giving him an endorsement ahead of the general election on 12 December.
Donald Trump has previously backed the prime minister, calling him “the exact right guy for the times”.
But during an interview with LBC, Mr Johnson said it was “best… for neither side to be involved in the other’s election campaigns”.
Mr Trump is due in the UK next week to join world leaders for a Nato summit.
Protests have been planned against the president to coincide with a banquet at Buckingham Palace, where the Queen will host him.
In an interview on LBC on Friday, Mr Johnson was asked if the support of the US president was “welcome”.