The Iron Lady has passed away at the age of 87. Sky News has more:
Baroness Thatcher has died at the age of 87 after suffering a stroke, her spokesman Lord Bell has announced.
Lord Bell 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."
Baroness Thatcher, Britain's first and only woman prime minister, had become increasingly frail and was suffering ill health in recent years.
She was admitted to hospital shortly before Christmas where she underwent an operation to remove a growth from her bladder but was allowed to return home before new year.
She will be deeply missed:
More from CNN:
Thatcher served from 1979 to 1990 as leader of the Conservative Party. She was called the "Iron Lady" for her personal and political toughness.
Thatcher retired from public life after a stroke in 2002 and suffered several strokes after that.
She made few public appearances in her final months, missing a reception marking her 85th birthday hosted by Prime Minister David Cameron in October 2010. She also skipped the July 2011 unveiling of a statue honoring her old friend Ronald Reagan in London.
Thatcher won the nation's top job only six years after declaring in a television interview, "I don't think there will be a woman prime minister in my lifetime."
During her time at the helm of the British government, she emphasized moral absolutism, nationalism, and the rights of the individual versus that of the state -- famously declaring, "There is no such thing as society" in 1987.
Nicknamed the "Iron Lady" by the Soviet press after a 1976 speech declaring that "the Russians are bent on world dominance," Thatcher later enjoyed a close working relationship with U.S. President Reagan, with whom she shared similar conservative views.
But the British cold warrior played a key role in ending the conflict by giving her stamp of approval to Soviet Communist reformer Mikhail Gorbachev shortly before he came to power.