When US president Donald Trump was heckled by a union worker in Michigan on Tuesday, the Republican appeared to respond by saying “f*** you” and giving the employee in question the middle finger – and the White House has said such a response was “appropriate and unambiguous”.

President Donald Trump toured an assembly line making Ford F-150 pickups on Tuesday, part of a Michigan trip meant to promote his efforts to boost U.S. manufacturing and counter fears about a weakening job market and still-rising prices hurting Americans' pocketbooks.