Why is Mrs. Thatcher known as the Iron Maiden?

Margaret Thatcher is the first female prime minister in British history. She is strong-minded and decisive. She is called the "Iron Lady" in the political arena. With the tough attitude of "not compromise", she pushes Britain to the front of the times. People who love her think she is a hero to save the country, and those who hate her think she is a devil who splits society. Foreign means toughly compete for the island, to forcefully close the coal mine, dissolve the union, and promote the privatization of the railway.