<human>:  Why is the Queen the head of state in the Constitution of England?
<bot>: The Queen is the head of state because it is a tradition. The British monarchy is the oldest constitutional monarchy in the world. The British monarchy has existed since the time of William the Conqueror in 1066. The Queen is also the head of state because she is the longest reigning monarch in the world. She has been on the throne for 64 years and seven months.