Gandhi's stress on the Congress-led government's massive expansion of welfare programmes with Modi's more "aspirational" messages aimed at India's youthful population. At least 120m first voters are estimated to be eligible to vote next year.

Gandhi said on Sunday that both mainstream parties were "thinking about politics in a traditional way". Congress would learn from the AAP's success and "involve people across the country in ways you cannot imagine right now", the 43-year-old former management consultant told reporters.

His mother, Sonia Gandhi, said the party would "accept the verdict of the people in all humility".

India's fragmented political landscape makes forthcoming national elections hard to predict, however. Historically, strong state results have not always translated into success in national elections.

And though last night AAP activists at its campaign headquarters said itCongress support from those at the bottom of India's caste system, the tenacious social hierarchy, appeared to be absent.

The AAP has argued that a new style of politics should ignore factors such as caste and focus on delivery of basic services, honest administration and transparency.

"I voted for Kejriwal because all the others are thieves. They tell us they will help us when they want our votes and then we never hear or see them again," said Mohan Lal, a 42-yea- old cobbler in west Delhi.

Marlena, the activist who is also one of the AAP's key policymakers, said the party was part of a broader, worldwide phenomenon, such as the political groups "coming out of people's movements" in Europe and the Middle East. The AAP has its roots in