For the Congress party, which has ruled over independent India for 54 of the past 67 years, the only thing in doubt about this general election is the scale of its defeat. After a decade of the increasingly feeble leadership of Manmohan Singh, the country’s 815m-strong electorate is in fierce anti-incumbency mood.

Voters are rejecting not only the past 10 years. There is a more fundamental backlash against the Delhi-centric politics of paternalism represented by the family-run business otherwise known as the Congress party. Narendra Modi, leader of the Hindu nationalist Bharatiya Janata party, is non-metropolitan, non-elite and - the son of a Gujarati tea seller - decidedly not a member of the Nehru-Gandhi dynasty. It would be hard to dream up anyone better placed to cash in politically on public disillusion.

The most common explanation for Congress’s impending implosion is that it has done a lousy job. Under its watch, India’s growth story has come off the rails. The rate of expansion has halved, something that cannot be said for the rate of corruption. Investment has stalled. Confidence has been sapped. In his second term, Mr Singh has been little more than a seat-warmer for Rahul Gandhi, the not-so-great great-grandson of Jawaharlal Nehru. There is some truth to this narrative. But there is another, counter-intuitive, explanation that sheds a different light on the state of modern India. This is that Congress, by making progress in its mission to eradicate poverty, has done itself out of a job.

It was Congress that in 1991 ditched its Nehruvian socialism and, forced on by crisis, unleashed India’s caged growth potential through market reforms. The BJP, which ran things from 1998 to 2004, built on that record by overseeing further economic expansion. Growth in the past decade under Congress has averaged 7.7pc, nothing to sneeze at. But, inconveniently, the rate has dipped below 5pc in the run-up to this election year. “We gave you eight good years and two lean years,” is how one senior government official puts it. That has been enough to more than double per capita income, which is now higher than $4,000 on a purchasing power basis, according to the International Monetary Fund.

India in 2014, in other words, is not the same country it was in 2004. Congress’s undoing is that it has failed to recognise this. It has instituted socially laudable right-to-work and right-to-food programmes. But such schemes are costly and prone to rampant theft. By putting a strain on the Treasury, they have contributed to persistent inflation. That in turn has forced the central bank to raise interest rates, slowing growth.

Worse, from an electoral - if not a humanitarian - standpoint the desperately poor are a shrinking constituency. If we take the government’s estimate of 22pc living in poverty, that means 935m Indians have escaped misery and are looking for something better. They have graduated from what Rajiv Kumar of the Centre for Policy Research calls the ‘petitioning’ class to the ‘aspirational’ one.

Most Indians are no longer satisfied with the make-work schemes or food handouts in which Congress has increasingly specialised. Many have caught the whiff of a better life. Now they want jobs and opportunity. Even those who have not yet clawed their way on to the bottom rung of the aspirational ladder have seen what it looks like, courtesy of the satellite television channels that beam images of a middle-class life into even the most benighted corners of the country. India’s villages are not what they once were. The bullock cart has given way to the motorbike; the dirt road to tarmac.

Mr Kumar says Congress is stuck in a time warp. It is addressing the needs of what novelist Aravind Adiga called ‘the Darkness’ of rural India. “But the whole notion of the legions outside the gates; that India has gone,” says Mr Kumar, with perhaps only slight exaggeration.

India is also undergoing a demographic transformation. An astonishing half of its 1.2bn people are below 26. In this election, results of which are due next week, 70m young voters are casting their ballot for the first time. They have no memory of the pre-1991 ‘Hindu rate of growth’. They know only an economy, that albeit haltingly and unevenly, offers the prospect of a gradually better life.

Sanjaya Baru, who has written an insider’s account of Mr Singh’s first term, argues that Congress has been too defensive about its record. Party bigwigs have put the blame for what has gone wrong on Mr Singh, while presenting Mr Gandhi, scion of the Nehru-Gandhi dynasty, as an improbable source of change. That is precisely the wrong message for a country that has outgrown feudal patronage. Mr Modi, who hails from outside the system, comes across as a far more plausible change agent.

The India that Congress is talking to is fast vanishing. It has failed to understand the magnitude of the social and economic changes it has helped create. Therein lies its downfall.