The hair is where the comparisons always start - although the Associated Press's Gregory Katz and Natasha Livingstone note that while both pay careful attention to their trademark coifs, they do so in differing ways.
"President Donald Trump's hair is very carefully styled before he appears in public, while Johnson's precisely the opposite," they write (in fact, Johnson is known to ruffle his hair before he goes on camera). "From the start of his political career Johnson has sported what could only be called the 'slept-on' look, declining to style his locks in any way so they have a natural, spontaneous, even unpredictable quality."
Beyond appearances, American observers note that both Mr Trump and Mr Johnson were born in New York City, and both have elite college pedigrees

