If one were to identify just five leaders who have decisively shaped Indian politics since Independence, and given it its distinctive character, Vishwanath Pratap Singh will surely figure among them.

Singh rose to national eminence in the early 1980s as a leader of exceptional sincerity and personal integrity. A quarter century on, he not only retains an untarnished personal reputation, but more important, remains a towering political personality, far more important than any former prime minister in India's history, with the exception of Indira Gandhi in the period 1977 to 1980.

Even more significant, Singh continues to have considerable political influence, especially in the Hindi heartland.

His abiding relevance was reaffirmed when he turned 75 on June 25 and was felicitated by a cross-section of people from different walks of life, including former civil servants, academics and the poorest of slum-dwellers from Delhi.

His birthday celebrations turned into a major occasion for leaders from different political currents, ranging from Prime Minister Manmohan Singh [Images] to Ram Vilas Paswan to the Communist parties' A B Bardhan and Sitaram Yechuri, to express solidarity with Singh and to show that they are willing to explore ways of working with him.

The event signified that Singh will have a major role in any political regroupment that occurs on the Centre-Left in the near future -- despite his rather complicated relationship with the Congress, which bristles each time he mentions Bofors. (In his just-released biography by journalist Ram Bahadur Rai, Singh claims that Bofors was willing to disclose the names of the recipients of the kickbacks in 1989-1990, but that the Congress scuttled the move.)

As noteworthy as the presence of an impressive spectrum of leaders at Singh's 75th birthday was the absence of both the Bharatiya Janata Party and the Samajwadi Party, who were at one time crucial to the formation and (brief) survival of the National Front government which Singh headed at the Centre in 1989-1990. Until recently, the Samajwadi Party and Singh were politically close to each other.

The reason for Singh's continued political relevance is not that he held power for long as India's prime minister. In fact, the National Front stayed in office for just 11 months, one of the shortest tenures of any government in New Delhi.

Nor would it be right to attribute Singh's relevance largely to his stature as the 'Mandal messiah', who extended affirmative action, in particular reservations in government employment, to the lower and lower-middle strata of society, or the Other (educationally and socially) Backward Classes -- OBCs.

That action of 16 years ago cannot alone explain the present.

The real reason for Singh's relevance lies in his special, probably unique, role as The Transition Man, who has bridged or spanned many divides in India. Singh was influenced in his youth by Socialist thought, but joined active politics under the Congress banner.

Yet, he quit the Congress in 1987 and became the biggest rallying point for non-Congress parties in the 1989 election. He has since continued to be a focal point in all attempts to mobilise Centre-Left forces on a broad anti-communal platform. No other person has offered so many links or bridges across different parts of the political spectrum.

Singh stands at another junction, marking India's shift from a leader-driver, top-down, manipulative system of politics, to a politics of self-assertion by the plebeian classes, which is more democratically accountable.

It is not that leaders no longer matter -- of course, they do. But in relation to the period until the 1980s, the masses, especially subordinate groups like Dalits and OBCs, have become far more vocal and demanding. They want self-representation, rather than patronage-based indirect representation on their behalf by others.

This is altering the character of Indian democracy by increasingly reshaping it into a system that is seen by the people as capable of empowering them -- not just as a system of exercising power over them. The change has helped formal democracy, based on procedures such as representation and elections along with Constitutional rules and parliamentary norms, acquire a more substantive character.

This shift makes India's current politics -- with its many flaws, but also with its robust, rambunctious and vibrant character -- qualitatively different from the anaemic democracies of numerous countries, including many developed ones. Singh is one of the leaders who catalysed this shift.

Singh forms another bridge: between public morality and politics, symbolised by Bofors and his resignation over the issue of lack of probity in public life. Bofors was not only India's largest corruption scandal until the mid-1980s. It was located at many crossroads: that between military and civilian decision-making, between foreign arms manufacturers and potential domestic recipients of bribes, and between them and middlemen like the Hindujas.

The Bofors investigation by the media, and by official agencies, turned up an unprecedented wealth of information, rare in such cases. Equally unprecedented was the public outcry over the scandal. With Bofors, V P Singh too became a household name.

Equally important is the link Singh has formed through his work in the last five years or more between political parties, on the one hand, and people's movements, non-party political groups and NGOs, on the other. Singh has tirelessly worked to defend the rights of slum-dwellers, rickshaw-pullers and other informal sector workers in the cities, and landless workers, Dalits and victims of displacement in the villages.

No political leader has done more for the Right to Information campaign in Rajasthan, Uttar Pradesh, Madhya Pradesh or Bihar than him. Whenever movements of the downtrodden and the desperately poor need help, he tries to reach out to them.

Only his amazing dedication to the underprivileged can explain why 12 years after he was detected to have a nasty cancer, as well as kidney failure, he continues to be extremely active among groups who are nobody's constituency.

Every week, he addresses dozens of public meetings and activists' discussions in different cities and towns, taking a break only for his thrice-weekly dialysis. It's the energy that he gets from these flesh-and-blood people, the salt of the Indian earth, that keeps him going.

None of this minimises the importance of Singh's decision to implement the Mandal Commission report. This was done at a particular juncture partly to counter the growing influence of Kamandal or Hindutva politics, which was then making thrust after offensive thrust against the secular pillars of Indian politics.

But the real significance of Mandal lay neither in this, nor in the circumstance that it opened 15 per cent of all central jobs for OBC recruitment -- barely 14,000 positions a year, or a drop in the ocean.

Rather, Mandal's true significance is that the decision held up a mirror to society as regards entrenched discrimination and mainstreamed the principle of affirmative action. Since 1990, wider acceptance and extension of affirmative action has become irreversible.

Only a highly regarded upper-caste leader of impeccable reputation like Singh could have dared take such a bold step given that violent opposition to it was a foregone conclusion. It redounds to his credit that he did so knowing this would topple his government.

As he himself dramatically puts it: "I scored a difficult goal, but in the process, I broke my leg irreparably!"

After the collapse of the United Front government in 1998, Singh concentrated on building up the political resources of secular parties although, in keeping with his decision to take sanyas from competitive politics, he didn't join any of them or create a new party. He brought to bear the power of his informal-sector mobilisation on the task of building a broad anti-communal front.

In the 2002 Uttar Pradesh election and in the last Lok Sabha campaign, he worked closely with the Centre-Left and regional parties, including the Samajwadi Party --because he regarded that as crucial to 'unhinging' the BJP from power. His input altered the outcome in a number of UP constituencies.

Now Singh has revived his Jan Morcha by joining hands with Raj Babbar, who was recently expelled from the Samajwadi Party. This has set him on a collision course with the Samajwadi Party and its backers. How this will influence the outcome of next year's election in UP is a big question. It seems likely that the Jan Morcha will erode the Samajwadi Party's base to some extent while indirectly helping the Congress and other non-BJP forces.

The outcome will also determine whether and how soon a Third Front independent of both the Congress and the BJP can be formed.

Whatever happens, platforms like Jan Morcha and poor people's organisations like Sajha Manch will continue to reshape public thinking in parts of India along broadly progressive lines. With them, the political space that V P Singh has come to represent will also expand.

One can only wish Singh well as he continues to fight for an equal, just and cooperative social order in which the poor can live with dignity and pursue the agenda of social emancipation.