Here are some key images from her time in power and the decade since she left stepped down.

Brave face: Leaving 10 Downing Street on the day of her resignation

A year later: With new PM John Major at the Conservative Party Conference in 1991

Face to face again: Margaret Thatcher and her successor John Major in 1999

Old rivals: Former Conservative Prime Ministers Sir Edward Heath and Baroness Thatcher ignore each other

Before they were really famous: Meeting a young William Hague at a party conference in 1977

Still in the wings: Supporting Conservative Party leader William Hague in 1999

Hands across the sea: Chatting with former US President Ronald Reagan in 1990

Forty winks: Baroness Thatcher famously only needed four hours sleep a night when she was prime minister