The Bharatiya Janata Party-led National Democratic Alliance is on a slide, an India Today-ORG MARG opinion poll has said predicting 242-252 seats, short of a simple majority, for the ruling combine in the next Lok Sabha election, down from 304 in 1999.

Congress and its allies, the poll said, are expected to gain 35-45 seats from the 140 bagged in the last general election.

Paradoxically, the opinion poll shows Atal Bihari Vajpayee's rating as the best prime ministerial choice remains a dozen points above Congress president Sonia Gandhi, though her popularity has risen six per cent.

According to the poll, the public disenchantment with the NDA government aggregated to a 0.43 per cent anti-incumbency swing across the country, which has the potential to translate into a loss of at least 57 seats.

The opinion poll says that the disaggregated picture is more alarming for the ruling combine -- relative swings of 3.5
per cent in the east, having 142 seats and 2.16 per cent in the north, having the highest number of 151 seats.

The survey covered 17,500 respondents spread across 98 parliamentary constituencies and was carried out between July 28 and August 6.

Apart from stagnancy in terms of votes, the BJP has begun losing ground in its erstwhile stronghold of Uttar Pradesh
despite a tie-up with Mayawati's Bahujan Samaj Party.

It is also trailing in Orissa, Jharkhand, Delhi, Haryana, Assam and in Andhra Pradesh as its regional allies face the brunt of public anger.