The British's opinion on Thatcher is very divided and split into two camps; those who hate her and those who admire her. The deep divisions continues to this very day, the view of Thatcher from one side is that she was responsible for the fall of the Trade Unions in the UK, and exhibited ruthless behaviour towards the miners and other blue-collar workers. However, those on the opposing side of the debate believe that Thatcher brought Britain back up from it's knees when it was facing a major financial crisis pre-1979 due to the aftermath of WW2 and the creation of the Welfare State in 1948.
Eventually after a decade in power, in 1990, mainly due to the public backlash of the Poll Tax, Thatcher was forced out of government by her own cabinet members and was succeeded by John Major.
It is likely that the British will a strong opinion on Thatcher for a long time yet, as demonstrated in some of defintions left by other users.
Margaret Thatcher is like marmite - you either love her or hate her.