Chief minister Mulayam Singh Yadav and leader of the opposition Lalji Tandon were among the prominent members of the state assembly to exercise their franchise in the opening hours.

The polling started at 9 am and will continue till 3 pm. Counting of votes would be taken up after 5 pm.

Meanwhile, some confusion prevailed in the polling hall with the opposition candidates accusing the ruling Samajwadi Party for mismanagement.

Independent candidate for the Rajya Sabha Sudhanshu Mittal said he would complain about it to the Election Commission and demand countermand of the polls.

Amid apprehension of cross voting, intimidation of voters and even use of money and muscle power by the political parties to garner support for their candidates, prominent political parties � Samajwadi Party, Bahujan Samaj Party, the Bharatiya Janata Party, Rashtriya Lok Dal, and Congress along with independents and smaller parties -- have taken all possible steps to keep their members united.

All eyes are, however, set on 37 rebel BSP legislators who had been recognised as a seperate group in the state assembly by the Supreme Court recently and the 16 independent legislators who hold the key to the electoral fate of 13 candidates in contention for 10 seats of RS and 14 candidates for the 13 legislative council seats in UP.

The BSP is all out to woo these 13 candidates. Five of them have already announced a switch to their original party.

Returning officer and state principal secretary (assembly) R P Pandey said the polling was underway on a peaceful note.

Pandey said although whip of political parties would not be effective for the elections, all the voters have to show their ballot papers to the political parties' agents before casting vote. The ballots of those who do not follow this rule would be rejected.

"Votes of all the legislators will be valid if they show their ballot papers to the agent, even if they vote against party whip."