Margaret Thatcher was the Prime Minister of the United Kingdom from 1979 to 1990 and is known for her policies that emphasized free-market principles and reduced government intervention. Key aspects of her government included privatization of state-owned enterprises, deregulation of the economy, and strong anti-union measures. Thatcher's leadership style and her focus on individualism and entrepreneurship transformed British politics and economics, earning her the nickname "The Iron Lady" due to her firm stance on various issues.