Margaret Thatcher has died after suffering a stroke, her spokesman has said.
Lord Bell, Baroness Thatcher's spokesman, confirmed the former prime minister has died at the age of 87.
A statement said: "It is with great sadness that Mark and Carol Thatcher announced that their mother Baroness Thatcher died peacefully following a stroke this morning. A further statement will be made later."
She had suffered from ill health for years and spent last Christmas in hospital after having an operation for abdominal pains.
Her husband, Denis died ten years ago and following his death, Thatcher paid tribute to him, saying when he was there, she was "never alone".
Two years later, she was diagnosed with dementia, which was confirmed by her daughter Carol, who said she repeatedly had had to tell her mother about her father's death.
Thatcher was admitted to St Thomas' Hospital in London in 2008 after collapsing at a House of Lords dinner.
She was invited to Downing Street for her 85th birthday by David Cameron but she could not attend because of ill health.
The following year she was invited to the wedding of Prince William and Kate Middleton, but again had to decline because of health reasons.