Radical Margaret Thatcher showed the power of character Leaders who change things need conviction, courage and luck. Margaret Thatcher had all three in abundance. By the time she was ousted by her own party in 1990, the Iron Lady's head had been turned by her 11 years in 10 Downing Street. She had become, as one of her cabinet ministers said to me at the time, slightly mad. She had certainly changed things. The cliché about Mrs Thatcher (Baroness Thatcher, as she was later known, never really suited her) is that she altered the way Britons thought about themselves and the way the world thought about Britain. Along the way, the state made way for the individual. That is about right. Many admire her still for her guts and grit - qualities that seem lost to the present generation of politicians; many, particularly in the old industrial heartlands of northern England and Scotland, revile her for the wholesale destruction of their communities. She was not the most successful Conservative prime minister of the 20th century - for the simple reason that this daughter of a shopkeeper was not really a Tory. More a radical really - even perhaps a Maoist. A disdain for ideology had once seen the Conservatives labelled the stupid party. Mrs Thatcher was nothing if not an ideologue. Nostalgic as she was for an earlier age of British greatness, she was no respecter of tradition or established institutions. Many post-Thatcherite Conservative MPs show the same restless disregard for their party's communitarian tradition. David Cameron's Big Society has flopped. It may yet turn out that one of her legacies will be the destruction of Burkean Toryism. Her accomplishments - rolling back the postwar British state, clipping more than the wings of an over-mighty trade union movement, replacing direction from Whitehall with liberal markets - would have seemed greater had the obituaries been written before the great financial crash of 2008. After decades of relative decline Britain was slipping into the deeper abyss of absolute decline. It needed something akin to the Thatcher revolution. Yet much of what went wrong in the British economy during the years before the crash had their roots in the unfettering of capitalism during the 1980s. Darwinian economics carries its own risks. As Britain's financial sector has shrunk, there has not been enough in the way of productive capacity elsewhere to fill the gap. Whatever happened, some now wonder ruefully, to all that North Sea oil revenue? Britain has a habit of producing leaders who are more revered overseas than at home. Winston Churchill emerged from the second world war as one of the giants of politics. The reaction of British voters was to throw him out of office. Tony Blair still struts his stuff on the international stage. At home, the only other 20th century leader to win three successive general elections, he is seen by a substantial slice of the electorate as the poodle who led Britain into a reckless American war in Iraq. It is the same for the Iron Lady. Her reputation shines more brightly in Washington - and probably Beijing - than it ever did in many British cities. Thatcher danced with Ronald Reagan and lectured François Mitterrand and Helmut Kohl. She won two wars - one against Argentina in the Falkland Islands, the other at home against the praetorian guard of the trade union movement, the National Union of Mineworkers. Yet global realities have reimposed themselves. Britain no longer looks quite the re-emerging power on the international stage. The legacy of her constant battles with Brussels is a Conservative party that now seems intent on detaching Britain from its own continent. As for the special relationship, the other anchor of Britain's postwar foreign policy, the intimacy and access have gone; and so has the relevance. She was right about the cold war and communism, but the cold war was ending as she left Downing Street. When Barack Obama looks at the world, the Pacific pulls his gaze from the Atlantic. Thatcher's career was a reminder that character and leadership can still shape events - the more potent now in an age when leaders in thrall to 24-hour rolling news more often count the avoidance of risk their most important priority. For a time during her reign - she seemed more than simply a prime minister - it seemed that Britain could defy the gravity of geopolitics. Privately, she was always more pragmatic than her not-for-turning public pronouncements ever admitted. The privatisation of much of state industry stopped short at the Royal Mail; her fights with the EU did not prevent her signing the Single European Act. But the resolve was real. Looking at Britain's present predicament - economic and political - it would be more than a stretch to say that she turned the tide of history. But she certainly interrupted it. Not many of today's politicians can lay the same claim.