Stephen Miller, immigration hardliner, in his own words

Trump's most controversial aide begins his first day as White House chief of staff

Stephen Miller, the influential architect of Donald Trump's aggressive immigration crackdown, is due to start as White House chief of staff today. His promotion has horrified many, handing even more power to the president's most controversial aide.

The 41-year-old has been with Trump since the beginning of the US president's political career - serving as a speechwriter during his 2016 presidential campaign - and has long been seen as a hardliner on the right, serving as the driving force behind first-term Trump policies such as family separation at the US-Mexico border and the travel ban on people from many Muslim-majority countries.