In 1959 she was elected to Parliament as Member of Parliament (MP) for Finchley, a north London constituency, which she continued to represent until she was made a member of the House of Lords (as Baroness Thatcher) in 1992.
British Prime Minister David Cameron said, "It was with great sadness that l learned of Lady Thatcher's death. We've lost a great leader, a great prime minister and a great Briton".
Buckingham Palace said the Queen was sad to hear the news and that she would be sending a private message of sympathy to the family.
Thatcher's legacy had a profound effect upon the policies of her successors, both Conservative and Labour, while her radical and sometimes confrontational approach defined her 11-year period at No 10, BBC said.
At home, the emerging doctrine of Thatcherism meant denationalisation of state-owned industry – the new word "privatisation" came into widespread use in many countries – and defeat of militant trade unionists, notably the National Union of Miners (NUM), whose year-long strike (1984-85) was bitter and traumatic, the Guardian said.
Prime Minister Manmohan Singh today expressed "deepest sadness" over the demise of Thatcher and said, "people of India join me in sending our sincerest condolences to the Thatcher family, the government and people of the United Kingdom."
Singh said Thatcher was "a transformative figure under whom the United Kingdom registered important progress" in the national and international arenas.
