What brought about Margaret Thatcher's downfall?
9 April 2013 Last updated at 12:08 BST
Baroness Thatcher, Britain's first female premier, was Conservative prime minister from 1979 to 1990 and won three successive general elections.
She has died "peacefully" after suffering a stroke while staying at the Ritz hotel in central London.
In the third of four Newsnight films, Martha Kearney considers what brought an end to Margaret Thatcher's political career - not the unions or the opposition or the electorate, but the Conservative politicians closest to her.