LONDON — Britain on Monday embarked on a period of mourning for its most transformative peacetime prime minister, Margaret Thatcher, whose death at age 87 provoked a wave of emotive reflection from a normally stoic nation still deeply divided by her legacy.
As her health declined in recent years, Thatcher had largely faded from public life, though she was occasionally spotted walking, with help, up the stairs of the Ritz Hotel.
And yet, such was her legacy that she was never far from the political debate in Britain. A recent release of letters from the Falklands War underscored the steely determination she showed in defending Britain’s interests, despite resistance inside and outside the nation.
On Monday, the political right particularly mourned the loss of its matriarch, a woman who reinvigorated the relevance of a nation that, when she came to power, had entered a period of accelerated decline.
‘‘Today is a truly sad day for our country,’’ said Prime Minister David Cameron, who hails from the Conservative Party, as Thatcher did. ‘‘As our first woman prime minister, Margaret Thatcher succeeded against all the odds. And the real thing about Margaret Thatcher is she did not just lead our country, she saved our country.’’
Even some on the left — who consider Thatcher the bane of the common man, a leader bent on destroying the welfare state — acknowledged the loss of a woman credited with creating the modern British state.
‘‘She reshaped the politics of a whole generation,’’ said Ed Miliband, head of the Labor Party, Thatcher’s nemesis. ‘‘The Labor Party disagreed with much of what she did and she will always remain a controversial figure. But we can disagree and also greatly respect her political achievements and her personal strength.’’
In the hours after her death was announced, tributes poured in from around the globe.
‘‘Margaret Thatcher was a great politician and a bright individual. She will go down in our memory and in history,’’ former Soviet leader Mikhail Gorbachev said. Thatcher served as an intermediary between Gorbachev and Ronald Reagan, developing strong relationships with both men.
Henry A. Kissinger, the former US secretary of state, said Thatcher was a ‘‘great leader’’ and a ‘‘good friend of the United States.’’
In Poland, Foreign Minister Radoslaw Sikorski said his country should erect a statue of the British leader. He praised Thatcher as ‘‘a fearless champion of liberty, stood up for captive nations, helped the free world win the Cold War.’’