..... Britain is a constitutional monarchy, and the Prime Minister is the country's chief executive. The king of England is only a nominal head of state, who is responsible for receiving other heads of state or attending international summits. He has the symbolic right to promulgate certain laws and has little real power. She can't interfere in matters discussed in parliament.

So the British prime minister is in power and there is no president.

The queen is the symbol of the king. Although she has no real power, she is still worthy of respect.