Rudy Giuliani delivered the blunt message “from one mayor to another” and told the London leader he should spend more time dealing with crime and less worrying about the US President’s visit.
It comes after Mr Khan granted permission for a 20ft inflatable blimp – which depicts Mr Trump as a baby in a nappy – to fly above Parliament during the President’s visit.
Mr Giuliani said: “Sadiq Khan should be ashamed of himself. He’s so busy attacking President Trump’s visit and, in the meantime, crime is spiralling in London. Maybe he should just do his job instead of attacking a world leader.”
Giuliani, 74, was mayor of New York bet ween 1994 and 2002, using a zero tolerance “broken window” theory to slash crime in the city, for which he was nominated for a Nobel prize. London under Mr Khan, 47, has seen its murder rate surpass New York’s, growing by 44 per cent over the past 12 months alone.
Mr Trump, 72, is due to visit the UK for four days from Thursday and former Labour MP Khan has been campaigning against it for more than a year, even though he did not oppose a recent visit by Turkish dictator President Recep Tayyip Erdogan.
Former mayor Giuliani, who now acts as Mr Trump’s lawyer, accused Khan of spending too much time politicising and not enough time tackling the city’s problems.
More than two million US tourists visit London each year and Giuliani warned that Khan is jeopardising billions of pounds in tourist revenue.
He said: “Many people who come to London are Americans. More than half of us in the US now support the President and even those who don’t support him, support his office.
“I would not like to go to a country where someone with the authority of a mayor was rallying people against them. It’s highly inappropriate. He’s probably suffering from some of the criticisms that President Trump has made on him which are valid.