Narendra Modi and Rahul Gandhi in race to be India’s next prime minister

One is a former tea boy, the other a Harvard and Cambridge-educated scion of India's biggest political dynasty. In a country of contrasts, the national elections starting on April 7 will be a battle of backgrounds.

Narendra Modi, a Hindu nationalist hardliner from the Bharatiya Janata Party (BJP), is the frontrunner to emerge as India's next prime minister from the nine-stage elections, which were announced yesterday.

From one of India's "backward castes", Modi, 63, grew up in a village in western Gujarat state where electricity was scarce and his father's tea stall earnings bought few luxuries.

His main opponent from the left-leaning Congress party, in power for a decade, is 43-year-old Rahul Gandhi, who was raised in leafy New Delhi surrounded by the trappings of power.

Gandhi's father, grandmother and great-grandfather were all prime ministers, while his Italian-born mother now runs the Congress party, which faces widespread voter discontent over corruption and weak economic growth.

Modi, who worked his way up through grass-roots Hindu groups and makes no effort to disguise his contempt for the Gandhis, derides his younger opponent as a shehzada (prince) and has mocked his lack of experience in office. While popular with upper-caste business people, the BJP candidate has sought to underline his humble roots in a bid to appeal to rural voters in the northern Hindi-speaking heartland who will decide the outcome of the world's biggest election.

"Rahul Gandhi feels shameful in fighting elections against a tea seller," Modi declared to a crowd in January, referring to the times he helped out his father at his stall beside a railway track.