The US President criticised the London Mayor for his response to the London Bridge terror attack.

Mr Khan subsequently said Mr Trump's planned state visit to the UK should not go ahead.

But Mr Johnson said there is "no reason" for the offer to be rescinded.

He told BBC Radio 4's Today programme: "I do not wish to interpose myself into a row between the Mayor of London and the President of the United States. I have been there myself, I have done that.

"What I will say is that as a former holder of Sadiq's office is that I think he is entirely right to say what he said to reassure the people of his city about the presence of armed officers on the streets and it is entirely right that he should speak as he should."

When asked whether he would be happy to welcome Mr Trump to the UK, he said: "Well, the invitation has been issued and accepted and I see no reason to change that but as far as what Sadiq Khan has said about the reassurances that he has offered the the people of London i think he was entirely right to speak in the way that he did."

He continued: "I don't wish to enter into a row between those two individuals who are I think probably perfectly able to stick up for themselves if I know them both.

"What I will say is that as the Mayor of London Sadiq was perfectly right to reassure the public about the presence of armed officers on the street."