Margaret Thatcher was the first female PM of which country?

Margaret Thatcher, famously known as the "Iron Lady," made history as the first female Prime Minister of the United Kingdom. She served from 1979 to 1990, becoming the longest-serving British Prime Minister of the 20th century. Her tenure was marked by significant economic and social reforms, including privatization and a strong stance against trade unions, which profoundly reshaped British society. She was a towering figure in conservative politics globally. Canada, the USA, and Australia have all had female leaders or prominent political figures, but Margaret Thatcher specifically held the highest political office in the UK, making her a unique and influential figure in British and world history.