Allan Conn told us, in relevant part,

comparing the UK Head of State with the American President isn't really the point. One is a political Head of State whilst the other is in reality more symbolic. Different systems completely. The real head of gvt in the UK is the Prime Minister.

You are mistaken in that comparison, Allan. "The other" you refer to is clearly the President of the U.S. Contrary to presidents of many countries (France, for example) the U.S. President is far from merely symbolic.

Whereas the prime minister is head of government (no mean position, admittedly), the president under the US system is BOTH the Head of State and the Head of Government.

Dave Oesterreich