IN HIS recent book, Courage: Eight Portraits, Gordon Brown praised the Burmese dissident Aung San Suu Kyi as a fearless prisoner of conscience battling a state with one of the worst human rights records in the world. So, where is Gordon Brown now Burma has been devastated, and the generals discredited, by cyclone Nargis? Courage seems suddenly to be in short supply in Number 10.

Apart from a token denunciation of the junta's "unacceptable" behaviour, Brown has largely absented himself form the worst natural disaster since the Asian tsunami. Yet we all remember how Gordon Brown leapt onto the international stage after the Boxing Day inundation in 2004. Then, he commanded the international stage; challenged the conscience of the developed world; campaigned, not just for emergency relief, but for the elimination of the debts of poor countries.

We could do with some of that spirit now. Brown may not be able to force the generals to step aside so the aid agencies can avert a humanitarian catastrophe, but he could at least do something. Why has it been left to the Liberal Democrat leader Nick Clegg to call for emergency food drops? Shouldn't Brown be holding talks with the chiefs of staff to see if Britain could help? No-one is talking about invading Burma, but Britain is one of the few countries that could organise airborne relief with naval back-up.

In terms of crude politics, it is astonishing Brown has not sought to minimise his domestic difficulties by reminding us of his anti-poverty initiatives of 2005, especially since the doubling of world food prices has undone much of what was achieved by the G8 Gleneagles summit that he inspired. Perhaps he doesn't want to remind us. Back then, Brown was one of the most influential political figures in the world - almost as influential as Bono or Saint Bob! As one of the most successful chancellors in modern history, Brown's command of economics was considered unmatched and leaders of the industrial nations hung on his every word. It all seems like such a long time ago.

When he was chancellor, Brown bestrode the world. Now, as prime minister, he can barely bestride the gutter outside Number 10. He has been forced into a desperate U-turn on the 10p tax rate, and has been defied by his protégé, Wendy Alexander, over a referendum on Scottish independence. Ten days ago, his party suffered its worst local election results since 1968, as Labour plunged to third place behind the LibDems in English local elections. Losing the mayorship of London to Boris Johnson has handed the Tories their first electoral victory since 1992. On Friday, Brown suffered Labour's worst opinion poll rating since records began as YouGov put Labour at 23% - 26 points behind the Tories on 49%.

We are witnessing one of the most astonishing reversals of fortune in modern political history. It's hardly original to say it has the quality of a Shakespearean tragedy, but that doesn't make it any less tragic. For those of us who have watched Brown over the past 30 years, it is almost as if he has become a different person. Where is the politician of courage and ambition who tried to make poverty history? Three years ago, Brown didn't need to prattle about his "moral compass". He didn't dither and prevaricate.

You couldn't have imagined the old Gordon getting into this muddle over the 10p tax rate, shamelessly appeasing the wealthy over tax relief, or dancing to the Daily Mail agenda over refuse collection, youth crime and cannabis reform. I'm almost tempted to believe the stories circulating Westminster about Brown having had a breakdown caused by the strain of public exposure. His wife Sarah recently told a women's magazine he is working 20-hour days.

Perhaps he is spending too many of those hours with the merchant bankers and PR people who run his private office. But Gordon Brown must surely know that he is a champion of the dispossessed or he is nothing. That is what people expected of him when he took over from Tony Blair; that was always his personal mission statement. Brown may not have been elected by vote, but when he became leader last summer he had a moral mandate to change direction.

Britain wanted out of Iraq; wanted an end to the sleaze of cash-for-honours; wanted the bonus culture of the City challenged; wanted some fairness restored to society, especially in areas such as housing. What the country didn't want was Blair minus the charisma. The British voters may not be socialists, but they have a gut revulsion to extreme disparities of wealth. They don't like seeing their children mired in debt before they are 30 and trying to raise a family in a two-bedroom flat.

After a decade of largely stagnant earnings, then the mortgage famine and food price inflation, there is anxiety stalking the suburbs. Witness all the press features about "making do and mending" as the middle classes feel the pinch. The credit crisis has turned us all into neo-marxists, resentful at the way the City financiers enriched themselves playing roulette on the derivatives market and are now demanding public money to recoup their losses. Has there been any time in the past 30 years when more people have felt the rich have lost their moral bearings? You have to go back to the Tory prime minister, Edward Heath, talking about the "unacceptable face of capitalism" back in 1972, during the last great banking and debt crisis.

The great mystery is why Gordon Brown has failed to respond to this new moral climate. It is right up his street. Why hasn't he been taking the super-rich to task over their lack of social responsibility, been demanding a new political settlement between capital and the people? Instead of handing billions to the banks, he should surely have focused discontent at the way they have cynically created a debt society and plundered our pensions in the process.

The financial crisis is a global one. Brown could have used his global profile to lead a global response, seeking international regulation of finance and controls on speculation in essential commodities like food. The alternative is a breakdown of international free trade. He could have used the Burmese cyclone to remind people, as he did once before, that we are all one planet, are interdependent, and that we must work together or end up returning to autarky, competitive devaluation, depression and war. That's what one of his heroes would have done. Unfortunately, it seems there are no heroes any more, at least not in Number 10.