Who was the first female to hold the position of Prime Minister in Britain?

Margaret Thatcher, often referred to as the "Iron Lady," holds a significant place in British political history. She served as Prime Minister from 1979 to 1990, making her the longest-serving British Prime Minister of the 20th century. Her time in office was marked by significant economic and social reforms, often referred to as "Thatcherism," which included privatization of state-owned industries and reducing the power of trade unions. Before becoming Prime Minister, she was a Member of Parliament for Finchley and served as Secretary of State for Education and Science. Therefore, the correct answer is Margaret Thatcher because she was the first, and so far only, female Prime Minister of the United Kingdom. The other options are incorrect: Mary Peters is a Northern Irish former athlete, Nicola Sturgeon is a Scottish politician who served as First Minister of Scotland, and Mary Poppins is a fictional character.