During the war in the Falklands, Thatcher had declared an exclusion zone of 200 nautical miles around the islands. She decided to sink the Argentine ship the Belgrano, despite it being 30 - 40 miles outside the exclusion zone that she had imposed. The ship was on a course bound for 'home'. Several hundred died, some were only 18/ 19 years old.
She played dirty. As a Brit, and someone who supports the defence of the Falklands, i can honestly say she should not have sank the Belgrano at that time.